this works now, ironed out shit and made stuff work

run.bash

@@ -1,4 +1,4 @@
-#!/bin/bash
+u!/bin/bash
 
 set -e  # exit if any command fails
 

run.bat

@@ -0,0 +1 @@
+python -m flask --app .\src\app.py run --host=0.0.0.0 --port=5000

src/app.py

@@ -37,7 +37,7 @@ def script():
 
 @app.route('/favicon.ico')
 def favicon():
-    return send_from_directory("templates", "favicon", "favicon.ico")
+    return send_from_directory("templates", "favicon.ico")
 
 @app.route('/')
 def index():

src/problem_loader.py

@@ -1,15 +0,0 @@
-import json
-import os
-import threading
-import time
-from models import db, Problem
-from flask import current_app
-
-def schedule_problem_reload(app, json_path, interval_hours=10):
-    def reload_loop():
-        while True:
-            with app.app_context():
-                load_problems_from_json(json_path)
-            time.sleep(interval_hours * 3600)
-    t = threading.Thread(target=reload_loop, daemon=True)
-    t.start()

src/problems/Palindrome/description.md

@@ -0,0 +1,60 @@
+## Problem: Check if a String is a Palindrome
+
+Given a string `s`, determine whether it reads the same forward and backward.
+Return `True` if it is a palindrome, otherwise return `False`.
+
+A **palindrome** is a sequence of characters that is identical when reversed.
+Comparison is **case-sensitive** and should consider all characters, including spaces and punctuation.
+
+---
+
+### Example 1
+
+**Input:**
+
+```
+s = "racecar"
+```
+
+**Output:**
+
+```
+True
+```
+
+**Explanation:**
+Reversing `"racecar"` results in `"racecar"`, which is the same as the original string.
+
+---
+
+### Example 2
+
+**Input:**
+
+```
+s = "hello"
+```
+
+**Output:**
+
+```
+False
+```
+
+**Explanation:**
+Reversing `"hello"` results in `"olleh"`, which is different from the original string.
+
+---
+
+### Constraints
+
+* `0 <= len(s) <= 10^5`
+* `s` may contain letters, digits, symbols, and spaces.
+
+---
+
+### Function Signature (Python)
+
+```python
+def palindrome(s: str) -> bool:
+```

src/problems/Palindrome/manifest.json

@@ -0,0 +1,7 @@
+{
+    "title": "Palindrome",
+    "description": "Find out wether or not a String is a Palindrome",
+    "description_md": "problems/Palindrome/description.md",
+    "test_code": "problems/Palindrome/test.py",
+    "difficulty": "medium"
+}

src/problems/Palindrome/test.py

@@ -0,0 +1,32 @@
+import unittest
+
+#<!-- User expected Function -->
+## def palindrome(s:str) -> bool:
+    ## return s == s[::-1]
+
+class TestSolution(unittest.TestCase):
+    def test_palindrome(self):
+        test_cases = [
+            ("racecar", True),          # Simple palindrome
+            ("hello", False),           # Not a palindrome
+            ("", True),                 # Empty string
+            ("a", True),                # Single character
+            ("madam", True),            # Palindrome word
+            ("Madam", False),           # Case-sensitive check
+            ("12321", True),            # Numeric string palindrome
+            ("123456", False),          # Numeric string non-palindrome
+        ]
+        print("\nFUNCTION OUTPUT TEST RESULTS")
+
+        for input_val, expected in test_cases:
+            try:
+                actual = palindrome(input_val)  # pyright: ignore[reportUndefinedVariable]
+                status = "✓ PASS" if actual == expected else "✗ FAIL"
+                print(f"{status} | Input: '{input_val}' -> Got: {actual} | Expected: {expected}")
+                self.assertEqual(actual, expected)
+            except Exception as e:
+                print(f"✗ ERROR | Input: '{input_val}' -> Exception: {e}")
+                raise
+
+if __name__ == "__main__":
+    unittest.main(verbosity=2)

src/problems/regex-phone/description.md

@@ -0,0 +1,58 @@
+# Phone Number Regular Expression Validation
+
+You are asked to write a function that checks if a given string is a valid phone number.
+
+A valid phone number must follow this format:
+
+```python
+123-456-7890
+```
+
+* It contains **3 digits**, followed by a **dash (-)**
+* Then another **3 digits**, followed by a **dash (-)**
+* Then exactly **4 digits**
+
+If the string matches this exact format, return **True**. Otherwise, return **False**.
+
+---
+
+### Example 1
+
+```python
+Input: "123-456-7890"
+Output: True
+```
+
+### Example 2
+
+```python
+Input: "1234567890"
+Output: False
+```
+
+### Example 3
+
+```python
+Input: "abc-def-ghij"
+Output: False
+```
+
+---
+
+### Function Signature
+
+```python
+import re
+
+def is_valid_phone_number(phone_number: str) -> bool:
+    return bool("Your Solution Here!")
+```
+
+---
+
+### Hint 🔑
+
+* Use the **`re`** (regular expression) library.
+* `\d` means “a digit” in regex.
+* You will need exactly **3 digits**, then a dash, then **3 digits**, another dash, then **4 digits**.
+* Anchors `^` (start of string) and `$` (end of string) can help ensure the whole string matches.

src/problems/regex-phone/manifest.json

@@ -0,0 +1,7 @@
+{
+    "title": "Regex Phonenumber",
+    "description": "A regex problem to match phone numbers in various formats.",
+    "description_md": "problems/regex-phone/description.md",
+    "difficulty": "hard",
+    "test_code": "problems/regex-phone/test.py"
+}

src/problems/regex-phone/test.py

@@ -0,0 +1,33 @@
+import re
+import unittest
+
+## def is_valid_phone_number(phone_number : str):
+    ## return bool(re.search(r"^(\d{3}-){2}\d{4}$", phone_number))
+
+import unittest
+
+class TestPhoneNumberRegex(unittest.TestCase):
+    def test_if_valid(self):
+        test_cases = [
+            ("123-456-7890", True),   # Valid format
+            ("111-222-3333", True),   # Another valid format
+            ("abc-def-ghij", False),  # Letters instead of digits
+            ("1234567890", False),    # Missing dashes
+            ("123-45-67890", False),  # Wrong grouping
+            ("12-3456-7890", False),  # Wrong grouping again
+            ("", False),              # Empty string
+        ]
+        print("\nPHONE NUMBER VALIDATION TEST RESULTS")
+
+        for phone, expected in test_cases:
+            try:
+                actual = is_valid_phone_number(phone)  # pyright: ignore[reportUndefinedVariable]
+                status = "✓ PASS" if actual == expected else "✗ FAIL"
+                print(f"{status} | Input: '{phone}' -> Got: {actual} | Expected: {expected}")
+                self.assertEqual(actual, expected)
+            except Exception as e:
+                print(f"✗ ERROR | Input: '{phone}' -> Exception: {e}")
+                raise
+
+if __name__ == "__main__":
+    unittest.main(verbosity=2)

src/static/index.css

@@ -1,24 +1,47 @@
 :root {
     --bg: #f6f8fb;
     --card: #fff;
+    --text: #0f172a;
     --muted: #6b7280;
     --accent: #2563eb;
+    --border: #e5e7eb;
+    --hover: #f3f4f6;
     --shadow: 0 4px 12px rgba(16, 24, 40, 0.06);
     --radius: 8px;
-    --mono: 'JetBrains Mono', monospace;
+    --mono: "JetBrains Mono", monospace;
 }
-* { box-sizing: border-box; margin: 0; padding: 0; }
+
-html, body {
+/* Dark mode variables */
+html.dark {
+    --bg: #0f172a;
+    --card: #1e293b;
+    --text: #f1f5f9;
+    --muted: #94a3b8;
+    --accent: #3b82f6;
+    --border: #334155;
+    --hover: #334155;
+    --shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
+}
+* {
+    box-sizing: border-box;
+    margin: 0;
+    padding: 0;
+}
+html,
+body {
     height: 100%;
 }
 body {
     font-family: Inter, sans-serif;
     background: var(--bg);
-    color: #0f172a;
+    color: var(--text);
     padding: 16px;
     display: flex;
     justify-content: center;
     align-items: center;
+    transition:
+        background-color 0.3s ease,
+        color 0.3s ease;
 }
 .wrap {
     width: 100%;
@@ -27,14 +50,49 @@ body {
 header {
     margin-bottom: 14px;
 }
+.header-content {
+    display: flex;
+    justify-content: center;
+    align-items: center;
+    position: relative;
+}
 header h1 {
+    text-align: center;
     font-size: 1.6rem;
-    color: #111827;
+    color: var(--text);
 }
 header p {
     color: var(--muted);
     font-size: 0.9rem;
 }
+.dark-mode-toggle {
+    position: absolute;
+    right: 0;
+    background: none;
+    border: 1px solid var(--border);
+    border-radius: var(--radius);
+    padding: 6px 10px;
+    cursor: pointer;
+    color: var(--text);
+    font-size: 1.2rem;
+    transition: all 0.3s ease;
+}
+.dark-mode-toggle:hover {
+    background: var(--hover);
+    transform: scale(1.05);
+}
+html.dark .dark-mode-icon::before {
+    content: "☀︎️";
+}
+html:not(.dark) .dark-mode-icon::before {
+    content: "⏾";
+}
+.dark-mode-icon {
+    display: inline-block;
+}
+.dark-mode-icon::before {
+    font-size: 1em;
+}
 .content {
     display: grid;
     grid-template-columns: 1fr 1fr;
@@ -58,32 +116,53 @@ header p {
 .search-input {
     flex: 1;
     padding: 6px 10px;
-    border: 1px solid #e5e7eb;
+    border: 1px solid var(--border);
     border-radius: 4px;
     font-size: 0.9rem;
+    background: var(--card);
+    color: var(--text);
+    transition: border-color 0.3s ease;
+}
+.search-input:focus {
+    outline: none;
+    border-color: var(--accent);
 }
 .filter-select {
     padding: 6px 8px;
-    border: 1px solid #e5e7eb;
+    border: 1px solid var(--border);
     border-radius: 4px;
     font-size: 0.9rem;
-    background: white;
+    background: var(--card);
+    color: var(--text);
+    transition: border-color 0.3s ease;
+}
+.filter-select:focus {
+    outline: none;
+    border-color: var(--accent);
 }
 /* Problems list */
 .problems-list .problem-item {
     padding: 8px;
-    border-bottom: 1px solid #e5e7eb;
+    border-bottom: 1px solid var(--border);
     display: flex;
     justify-content: space-between;
     align-items: center;
+    transition: background-color 0.3s ease;
+}
+.problem-item:hover {
+    background: var(--hover);
 }
 .problem-item:last-child {
     border-bottom: none;
 }
 .problem-item a {
     text-decoration: none;
-    color: #0077ff;
+    color: var(--accent);
     font-weight: 600;
+    transition: color 0.3s ease;
+}
+.problem-item a:hover {
+    text-decoration: underline;
 }
 /* Difficulty badge */
 .difficulty {
@@ -98,14 +177,14 @@ header p {
     white-space: nowrap;
 }
 .difficulty[data-difficulty="easy"] {
-    background-color: #4CAF50; /* Green */
+    background-color: #4caf50; /* Green */
 }
 .difficulty[data-difficulty="medium"] {
-    background-color: #FFC107; /* Amber */
+    background-color: #ffc107; /* Amber */
     color: #333;
 }
 .difficulty[data-difficulty="hard"] {
-    background-color: #F44336; /* Red */
+    background-color: #f44336; /* Red */
 }
 /* Leaderboard */
 .leaderboard-head {
@@ -127,16 +206,16 @@ header p {
 .leaderboard-table th,
 .leaderboard-table td {
     padding: 6px 8px;
-    border-bottom: 1px solid #e5e7eb;
+    border-bottom: 1px solid var(--border);
     text-align: left;
 }
 .leaderboard-table th {
-    background: #f9fafb;
+    background: var(--hover);
     font-weight: 600;
     color: var(--muted);
 }
 .leaderboard-table tr:hover {
-    background: #f3f4f6;
+    background: var(--hover);
 }
 /* Sort indicators */
 .sortable {
@@ -178,8 +257,70 @@ header p {
     background: rgba(37, 99, 235, 0.15);
 }
 @media (max-width: 800px) {
-    .content { grid-template-columns: 1fr; }
+    .content {
+        grid-template-columns: 1fr;
+    }
     .leaderboard-controls {
         flex-direction: column;
     }
 }
+
+/* Leaderboard horizontal collapse */
+#leaderboardSection {
+    transition:
+        max-width 0.35s ease,
+        opacity 0.25s ease;
+    overflow: hidden;
+    max-width: 100%;
+}
+
+#leaderboardSection.hidden {
+    max-width: 0;
+    opacity: 0;
+    pointer-events: none;
+}
+
+#leaderboardSection.visible {
+    max-width: 100%; /* take full available space in grid column */
+    opacity: 1;
+}
+#rankingExplanation {
+    transition: all 0.35s ease;
+}
+
+/* Pagination Controls */
+.pagination-controls {
+    display: flex;
+    justify-content: space-between;
+    align-items: center;
+    margin-top: 12px;
+    padding-top: 12px;
+    border-top: 1px solid var(--border);
+}
+.pagination-btn {
+    background: var(--card);
+    border: 1px solid var(--border);
+    border-radius: 4px;
+    padding: 6px 12px;
+    cursor: pointer;
+    color: var(--text);
+    font-size: 0.9rem;
+    transition: all 0.3s ease;
+}
+.pagination-btn:hover:not(:disabled) {
+    background: var(--hover);
+    border-color: var(--accent);
+}
+.pagination-btn:disabled {
+    opacity: 0.5;
+    cursor: not-allowed;
+}
+.pagination-info {
+    color: var(--muted);
+    font-size: 0.9rem;
+}
+
+/* Hide pagination when not needed */
+.pagination-controls.hidden {
+    display: none;
+}

src/static/problem.css

@@ -0,0 +1,296 @@
+:root {
+    --bg: #f9f9f9;
+    --card: #fff;
+    --text: #333;
+    --muted: #666;
+    --accent: #007bff;
+    --accent-hover: #0069d9;
+    --border: #eaeaea;
+    --hover: #f8f9fa;
+    --code-bg: #f6f8fa;
+    --editor-border: #ddd;
+}
+
+html.dark {
+    --bg: #0f172a;
+    --card: #1e293b;
+    --text: #f1f5f9;
+    --muted: #94a3b8;
+    --accent: #3b82f6;
+    --accent-hover: #2563eb;
+    --border: #334155;
+    --hover: #334155;
+    --code-bg: #1e293b;
+    --editor-border: #475569;
+}
+
+body {
+    font-family: "Inter", sans-serif;
+    margin: 0;
+    padding: 0;
+    background-color: var(--bg);
+    color: var(--text);
+    min-height: 100vh; /* allow content to grow */
+    overflow-y: auto; /* allow vertical scroll */
+    box-sizing: border-box;
+    transition:
+        background-color 0.3s ease,
+        color 0.3s ease;
+}
+
+*,
+*::before,
+*::after {
+    box-sizing: inherit;
+}
+
+.main-container {
+    display: flex;
+    flex-wrap: wrap; /* wrap on small screens */
+    min-height: 100vh;
+    width: 100vw;
+}
+
+.problem-panel {
+    flex: 1 1 400px; /* grow/shrink with base 400px */
+    min-width: 300px;
+    background: var(--card);
+    overflow-y: auto;
+    padding: 20px;
+    border-right: 1px solid var(--border);
+    max-height: 100vh;
+    transition: background-color 0.3s ease;
+}
+
+.editor-container {
+    flex: 1 1 400px;
+    min-width: 300px;
+    display: flex;
+    flex-direction: column;
+    background: var(--card);
+    max-height: 100vh;
+    overflow: hidden; /* internal scroll handling */
+    transition: background-color 0.3s ease;
+}
+
+.editor-header {
+    padding: 15px 20px;
+    border-bottom: 1px solid var(--border);
+    flex-shrink: 0;
+}
+
+.editor-wrapper {
+    flex: 1 1 auto;
+    display: flex;
+    flex-direction: column;
+    min-height: 0;
+    padding: 0 20px;
+    overflow-y: auto;
+}
+
+.problem-header {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    margin-bottom: 20px;
+}
+
+.back-btn {
+    background: none;
+    border: 1px solid var(--border);
+    border-radius: 4px;
+    cursor: pointer;
+    font-size: 16px;
+    color: var(--muted);
+    margin-right: 15px;
+    padding: 6px 10px;
+    transition: all 0.3s ease;
+}
+
+.back-btn:hover {
+    color: var(--text);
+    background: var(--hover);
+}
+
+.dark-mode-toggle {
+    background: none;
+    border: 1px solid var(--border);
+    border-radius: 4px;
+    padding: 6px 10px;
+    cursor: pointer;
+    color: var(--text);
+    font-size: 1.2rem;
+    transition: all 0.3s ease;
+}
+
+.dark-mode-toggle:hover {
+    background: var(--hover);
+    transform: scale(1.05);
+}
+
+html.dark .dark-mode-icon::before {
+    content: "☀";
+}
+
+html:not(.dark) .dark-mode-icon::before {
+    content: "⏾";
+}
+
+.dark-mode-icon {
+    display: inline-block;
+}
+
+.dark-mode-icon::before {
+    font-size: 1em;
+}
+
+h1 {
+    font-size: 22px;
+    font-weight: 600;
+    margin: 0;
+    color: var(--text);
+    flex: 1;
+}
+
+.problem-desc {
+    line-height: 1.6;
+    font-size: 15px;
+    overflow-wrap: break-word;
+}
+
+.problem-desc pre {
+    background: var(--code-bg);
+    padding: 12px;
+    border-radius: 4px;
+    overflow-x: auto;
+    font-family: "JetBrains Mono", monospace;
+    font-size: 14px;
+    border: 1px solid var(--border);
+}
+
+.problem-desc code {
+    background: var(--code-bg);
+    padding: 2px 4px;
+    border-radius: 3px;
+    font-family: "JetBrains Mono", monospace;
+    font-size: 14px;
+}
+
+.editor-actions {
+    padding: 15px 0;
+    display: flex;
+    justify-content: flex-end;
+    flex-shrink: 0;
+}
+
+.editor-actions button {
+    background-color: var(--accent);
+    color: white;
+    border: none;
+    padding: 8px 16px;
+    border-radius: 4px;
+    cursor: pointer;
+    font-weight: 500;
+    font-size: 14px;
+    transition: background-color 0.3s ease;
+}
+
+.editor-actions button:hover {
+    background-color: var(--accent-hover);
+}
+
+#editor {
+    flex: 1 1 auto;
+    min-height: 300px;
+    border: 1px solid var(--editor-border);
+    border-radius: 4px;
+    overflow: auto;
+    max-height: 60vh;
+}
+
+.result-panel {
+    margin-top: 20px;
+    padding: 15px;
+    background: var(--hover);
+    border-radius: 4px;
+    margin-bottom: 20px;
+    min-height: 120px;
+    overflow-y: auto;
+    max-height: 30vh;
+    border: 1px solid var(--border);
+    transition: background-color 0.3s ease;
+}
+
+.result-panel h3 {
+    margin-top: 0;
+    font-size: 16px;
+    margin-bottom: 10px;
+}
+
+.result-panel pre {
+    background: var(--code-bg);
+    padding: 12px;
+    border-radius: 4px;
+    overflow-x: auto;
+    white-space: pre-wrap;
+    font-family: "JetBrains Mono", monospace;
+    font-size: 14px;
+    margin: 5px 0;
+    border: 1px solid var(--border);
+}
+
+.placeholder {
+    color: var(--muted);
+    font-style: italic;
+    text-align: center;
+    padding: 20px;
+}
+
+label {
+    display: block;
+    margin-bottom: 5px;
+    font-size: 14px;
+    color: var(--muted);
+}
+
+input[type="text"] {
+    width: 100%;
+    padding: 8px;
+    border: 1px solid var(--border);
+    border-radius: 4px;
+    margin-bottom: 15px;
+    font-family: "Inter", sans-serif;
+    background: var(--card);
+    color: var(--text);
+    transition: border-color 0.3s ease;
+}
+
+input[type="text"]:focus {
+    outline: none;
+    border-color: var(--accent);
+}
+
+/* Responsive adjustments */
+@media (max-width: 768px) {
+    .main-container {
+        flex-direction: column;
+        height: auto;
+        overflow-y: visible;
+    }
+    .problem-panel,
+    .editor-container {
+        flex: none;
+        width: 100%;
+        min-width: auto;
+        max-height: none;
+        border-right: none;
+        border-bottom: 1px solid var(--border);
+    }
+    #editor {
+        min-height: 400px;
+        max-height: none;
+    }
+    .result-panel {
+        max-height: none;
+    }
+}

src/static/script.js

@@ -0,0 +1,403 @@
+document.addEventListener("DOMContentLoaded", () => {
+  // Dark mode functionality
+  const darkModeToggle = document.getElementById("darkModeToggle");
+  const html = document.documentElement;
+
+  // Load saved dark mode preference
+  const savedDarkMode = localStorage.getItem("darkMode");
+  if (
+    savedDarkMode === "true" ||
+    (savedDarkMode === null &&
+      // detect if the user already has a dark mode enabled in the system settings ( works for all systems )
+      window.matchMedia("(prefers-color-scheme: dark)").matches)
+  ) {
+    html.classList.add("dark");
+  }
+
+  darkModeToggle?.addEventListener("click", () => {
+    html.classList.toggle("dark");
+    localStorage.setItem("darkMode", html.classList.contains("dark"));
+  });
+
+  // Problem search and pagination
+  const problemSearch = document.getElementById("problemSearch");
+  const problemsContainer = document.getElementById("problemsContainer");
+  const problemsPagination = document.getElementById("problemsPagination");
+  const problemsPrevBtn = document.getElementById("problemsPrevBtn");
+  const problemsNextBtn = document.getElementById("problemsNextBtn");
+  const problemsPaginationInfo = document.getElementById(
+    "problemsPaginationInfo",
+  );
+
+  let allProblemItems = [];
+  let filteredProblemItems = [];
+  let currentPage = 1;
+  const itemsPerPage = 5;
+
+  // Initialize problem items
+  function initializeProblemItems() {
+    allProblemItems = Array.from(
+      problemsContainer?.querySelectorAll(".problem-item") || [],
+    );
+    filteredProblemItems = [...allProblemItems];
+    updatePagination();
+  }
+
+  function updatePagination() {
+    const totalPages = Math.ceil(filteredProblemItems.length / itemsPerPage);
+    const startIndex = (currentPage - 1) * itemsPerPage;
+    const endIndex = startIndex + itemsPerPage;
+
+    // Hide all items first
+    allProblemItems.forEach((item) => {
+      item.style.display = "none";
+    });
+
+    // Show current page items
+    filteredProblemItems.slice(startIndex, endIndex).forEach((item) => {
+      item.style.display = "";
+    });
+
+    // Update pagination controls
+    if (problemsPrevBtn) problemsPrevBtn.disabled = currentPage <= 1;
+    if (problemsNextBtn) problemsNextBtn.disabled = currentPage >= totalPages;
+    if (problemsPaginationInfo) {
+      problemsPaginationInfo.textContent =
+        totalPages > 0
+          ? `Page ${currentPage} of ${totalPages}`
+          : "No problems found";
+    }
+
+    // Hide pagination if not needed
+    if (problemsPagination) {
+      problemsPagination.classList.toggle("hidden", totalPages <= 1);
+    }
+  }
+
+  function filterProblems() {
+    const term = problemSearch?.value.toLowerCase().trim() || "";
+    filteredProblemItems = allProblemItems.filter((item) => {
+      const name = item.dataset.name?.toLowerCase() || "";
+      const desc = item.dataset.desc?.toLowerCase() || "";
+      return !term || name.includes(term) || desc.includes(term);
+    });
+    currentPage = 1;
+    updatePagination();
+  }
+
+  // Event listeners for pagination
+  problemsPrevBtn?.addEventListener("click", () => {
+    if (currentPage > 1) {
+      currentPage--;
+      updatePagination();
+    }
+  });
+
+  problemsNextBtn?.addEventListener("click", () => {
+    const totalPages = Math.ceil(filteredProblemItems.length / itemsPerPage);
+    if (currentPage < totalPages) {
+      currentPage++;
+      updatePagination();
+    }
+  });
+
+  problemSearch?.addEventListener("input", filterProblems);
+
+  // Initialize problems pagination
+  if (problemsContainer) {
+    initializeProblemItems();
+  }
+
+  // Leaderboard functionality
+  const problemFilter = document.getElementById("problemFilter");
+  const runtimeFilter = document.getElementById("runtimeFilter");
+  const leaderboardBody = document.getElementById("leaderboardBody");
+  const sortableHeaders = document.querySelectorAll(".sortable");
+
+  let currentSort = { column: "rank", direction: "asc" };
+  let allRows = [];
+
+  // Initialize rows array
+  function initializeRows() {
+    allRows = Array.from(leaderboardBody.querySelectorAll("tr")).map((row) => {
+      return {
+        element: row,
+        user: row.dataset.user || "",
+        problem: row.dataset.problem || "",
+        runtime: parseFloat(row.dataset.runtime) || 0,
+        memory: parseFloat(row.dataset.memory) || 0,
+        timestamp: new Date(row.dataset.timestamp || Date.now()).getTime(),
+        language: row.dataset.language || "",
+        originalIndex: Array.from(leaderboardBody.children).indexOf(row),
+      };
+    });
+  }
+
+  function updateRankClasses() {
+    const visibleRows = allRows.filter(
+      (row) => row.element.style.display !== "none",
+    );
+    visibleRows.forEach((rowData, index) => {
+      const rank = index + 1;
+      const row = rowData.element;
+
+      // Update rank cell
+      const rankCell = row.cells[0];
+      if (rankCell) rankCell.textContent = rank;
+
+      // Update rank classes
+      row.className = row.className.replace(/\brank-\d+\b/g, "");
+      if (rank === 1) row.classList.add("rank-1");
+      else if (rank <= 3) row.classList.add("rank-top3");
+    });
+  }
+
+  function calculateOverallRanking() {
+    const visibleRows = allRows.filter(
+      (row) => row.element.style.display !== "none",
+    );
+
+    if (visibleRows.length === 0) return;
+
+    // Group submissions by problem to find the best performance for each
+    const problemBests = {};
+
+    visibleRows.forEach((rowData) => {
+      const problem = rowData.problem;
+      if (!problemBests[problem]) {
+        problemBests[problem] = {
+          bestRuntime: Infinity,
+          bestMemory: Infinity,
+        };
+      }
+
+      problemBests[problem].bestRuntime = Math.min(
+        problemBests[problem].bestRuntime,
+        rowData.runtime,
+      );
+      problemBests[problem].bestMemory = Math.min(
+        problemBests[problem].bestMemory,
+        rowData.memory,
+      );
+    });
+
+    // Calculate normalized scores for each submission
+    visibleRows.forEach((rowData) => {
+      const problemBest = problemBests[rowData.problem];
+
+      // Prevent division by zero
+      const runtimeScore =
+        problemBest.bestRuntime > 0
+          ? rowData.runtime / problemBest.bestRuntime
+          : 1;
+      const memoryScore =
+        problemBest.bestMemory > 0
+          ? rowData.memory / problemBest.bestMemory
+          : 1;
+
+      // Weighted overall score (70% runtime, 30% memory)
+      rowData.overallScore = runtimeScore * 0.7 + memoryScore * 0.3;
+    });
+
+    // Sort by overall score (lower is better), then by timestamp (earlier is better for ties)
+    visibleRows.sort((a, b) => {
+      const scoreDiff = a.overallScore - b.overallScore;
+      if (Math.abs(scoreDiff) > 0.000001) return scoreDiff; // Use small epsilon for float comparison
+
+      // If scores are essentially equal, prefer earlier submission
+      return a.timestamp - b.timestamp;
+    });
+
+    // Reorder DOM elements and update ranks
+    visibleRows.forEach((rowData, index) => {
+      leaderboardBody.appendChild(rowData.element);
+    });
+
+    updateRankClasses();
+  }
+
+  function filterLeaderboard() {
+    const problemTerm = (problemFilter?.value || "").toLowerCase().trim();
+    const runtimeType = runtimeFilter?.value || "all";
+
+    // Reset all rows to visible first
+    allRows.forEach((rowData) => {
+      rowData.element.style.display = "";
+    });
+
+    // Apply problem filter
+    if (problemTerm) {
+      allRows.forEach((rowData) => {
+        const problemMatch = rowData.problem
+          .toLowerCase()
+          .includes(problemTerm);
+        if (!problemMatch) {
+          rowData.element.style.display = "none";
+        }
+      });
+    }
+
+    // Apply runtime filter (best/worst per user per problem)
+    if (runtimeType === "best" || runtimeType === "worst") {
+      const userProblemGroups = {};
+
+      // Group by user + problem combination
+      allRows.forEach((rowData) => {
+        if (rowData.element.style.display === "none") return;
+
+        const key = `${rowData.user}::${rowData.problem}`;
+        if (!userProblemGroups[key]) {
+          userProblemGroups[key] = [];
+        }
+        userProblemGroups[key].push(rowData);
+      });
+
+      // Hide all except best/worst for each user-problem combination
+      Object.values(userProblemGroups).forEach((group) => {
+        if (group.length <= 1) return;
+
+        // Sort by runtime
+        group.sort((a, b) => a.runtime - b.runtime);
+
+        const keepIndex = runtimeType === "best" ? 0 : group.length - 1;
+        group.forEach((rowData, index) => {
+          if (index !== keepIndex) {
+            rowData.element.style.display = "none";
+          }
+        });
+      });
+    }
+
+    calculateOverallRanking();
+  }
+
+  function getCellValue(rowData, column) {
+    switch (column) {
+      case "rank":
+        return parseInt(rowData.element.cells[0]?.textContent) || 0;
+      case "user":
+        return rowData.user.toLowerCase();
+      case "problem":
+        return rowData.problem.toLowerCase();
+      case "runtime":
+        return rowData.runtime;
+      case "memory":
+        return rowData.memory;
+      case "timestamp":
+        return rowData.timestamp;
+      case "language":
+        return rowData.language.toLowerCase();
+      default:
+        return "";
+    }
+  }
+
+  function sortLeaderboard(column, direction) {
+    if (column === "rank") {
+      calculateOverallRanking();
+      return;
+    }
+
+    const visibleRows = allRows.filter(
+      (row) => row.element.style.display !== "none",
+    );
+
+    visibleRows.sort((a, b) => {
+      const valueA = getCellValue(a, column);
+      const valueB = getCellValue(b, column);
+
+      let comparison = 0;
+      if (typeof valueA === "number" && typeof valueB === "number") {
+        comparison = valueA - valueB;
+      } else {
+        comparison = valueA < valueB ? -1 : valueA > valueB ? 1 : 0;
+      }
+
+      return direction === "asc" ? comparison : -comparison;
+    });
+
+    // Reorder DOM elements
+    visibleRows.forEach((rowData) => {
+      leaderboardBody.appendChild(rowData.element);
+    });
+
+    updateRankClasses();
+  }
+
+  // Event listeners for sorting
+  sortableHeaders.forEach((header) => {
+    header.addEventListener("click", () => {
+      const column = header.dataset.sort;
+      if (!column) return;
+
+      // Remove sorting classes from all headers
+      sortableHeaders.forEach((h) =>
+        h.classList.remove("sort-asc", "sort-desc"),
+      );
+
+      // Toggle sort direction
+      if (currentSort.column === column) {
+        currentSort.direction =
+          currentSort.direction === "asc" ? "desc" : "asc";
+      } else {
+        currentSort.column = column;
+        currentSort.direction = "asc";
+      }
+
+      // Add sorting class to current header
+      header.classList.add(`sort-${currentSort.direction}`);
+
+      sortLeaderboard(column, currentSort.direction);
+    });
+  });
+
+  // Filter event listeners
+  problemFilter?.addEventListener("input", filterLeaderboard);
+  runtimeFilter?.addEventListener("change", filterLeaderboard);
+
+  // Rank info popout
+  const rankInfoBtn = document.getElementById("rankInfoBtn");
+  const rankingExplanation = document.getElementById("rankingExplanation");
+
+  rankInfoBtn?.addEventListener("click", (e) => {
+    e.preventDefault();
+    rankingExplanation?.classList.toggle("active");
+    rankInfoBtn?.classList.toggle("active");
+  });
+
+  // Close ranking explanation when clicking outside
+  document.addEventListener("click", (e) => {
+    if (
+      rankingExplanation?.classList.contains("active") &&
+      !rankingExplanation.contains(e.target) &&
+      !rankInfoBtn?.contains(e.target)
+    ) {
+      rankingExplanation.classList.remove("active");
+      rankInfoBtn?.classList.remove("active");
+    }
+  });
+
+  // Initialize everything
+  if (leaderboardBody && leaderboardBody.children.length > 0) {
+    initializeRows();
+    calculateOverallRanking();
+
+    // Set initial sort indicator
+    const defaultHeader = document.querySelector('[data-sort="rank"]');
+    if (defaultHeader) {
+      defaultHeader.classList.add("sort-asc");
+    }
+  }
+
+  // Apply dark mode to dynamically created elements
+  function applyDarkModeToElements() {
+    const isDark = html.classList.contains("dark");
+    // Any additional dark mode styling for dynamically created elements can go here
+  }
+
+  // Watch for dark mode changes
+  new MutationObserver(applyDarkModeToElements).observe(html, {
+    attributes: true,
+    attributeFilter: ["class"],
+  });
+});

src/static/style.css

@@ -1,3 +1,49 @@
+:root {
+    --bg: #f8f9fa;
+    --card: #fff;
+    --text: #333;
+    --heading: #2c3e50;
+    --heading-secondary: #34495e;
+    --accent: #3498db;
+    --accent-hover: #2980b9;
+    --success: #27ae60;
+    --success-hover: #229954;
+    --error: #e74c3c;
+    --muted: #6c757d;
+    --muted-hover: #5a6268;
+    --border: #ddd;
+    --code-bg: #f4f4f4;
+    --success-bg: #d4edda;
+    --success-text: #155724;
+    --error-bg: #f8d7da;
+    --error-text: #721c24;
+    --hover-bg: #e3f2fd;
+    --shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
+}
+
+html.dark {
+    --bg: #0f172a;
+    --card: #1e293b;
+    --text: #f1f5f9;
+    --heading: #3b82f6;
+    --heading-secondary: #94a3b8;
+    --accent: #3b82f6;
+    --accent-hover: #2563eb;
+    --success: #22c55e;
+    --success-hover: #16a34a;
+    --error: #ef4444;
+    --muted: #64748b;
+    --muted-hover: #475569;
+    --border: #334155;
+    --code-bg: #1e293b;
+    --success-bg: #065f46;
+    --success-text: #d1fae5;
+    --error-bg: #7f1d1d;
+    --error-text: #fecaca;
+    --hover-bg: #1e40af;
+    --shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
+}
+
 /* Reset and base styles */
 * {
     margin: 0;
@@ -6,39 +52,43 @@
 }
 
 body {
-    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
+    font-family:
+        -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
     line-height: 1.6;
-    color: #333;
+    color: var(--text);
-    background-color: #f8f9fa;
+    background-color: var(--bg);
     padding: 20px;
     max-width: 1200px;
     margin: 0 auto;
+    transition:
+        background-color 0.3s ease,
+        color 0.3s ease;
 }
 
 /* Main heading */
 h1 {
-    color: #2c3e50;
+    color: var(--heading);
     margin-bottom: -10px;
     padding-bottom: 3px;
-    border-bottom: 3px solid #3498db;
+    border-bottom: 3px solid var(--accent);
     font-size: 2.2em;
 }
 
 h2 {
-    color: #34495e;
+    color: var(--heading-secondary);
     margin: 30px 0 20px 0;
     font-size: 1.5em;
 }
 
 h3 {
-    color: #34495e;
+    color: var(--heading-secondary);
     margin: 25px 0 15px 0;
     font-size: 1.3em;
 }
 
 /* Links and buttons */
 a {
-    color: #3498db;
+    color: var(--accent);
     text-decoration: none;
     padding: 8px 16px;
     border-radius: 5px;
@@ -46,13 +96,13 @@ a {
 }
 
 a:hover {
-    background-color: #e3f2fd;
+    background-color: var(--hover-bg);
     text-decoration: none;
 }
 
 /* Primary action link (Submit New Problem) */
 a[href="/problem/new"] {
-    background-color: #3498db;
+    background-color: var(--accent);
     color: white;
     font-weight: 600;
     margin-bottom: 30px;
@@ -62,22 +112,23 @@ a[href="/problem/new"] {
 }
 
 a[href="/problem/new"]:hover {
-    background-color: #2980b9;
+    background-color: var(--accent-hover);
 }
 
 /* Problem list */
 ul {
     list-style: none;
-    background: white;
+    background: var(--card);
     border-radius: 8px;
-    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
+    box-shadow: var(--shadow);
     padding: 25px;
     margin: 20px 0;
+    transition: background-color 0.3s ease;
 }
 
 li {
     padding: 15px 0;
-    border-bottom: 1px solid #eee;
+    border-bottom: 1px solid var(--border);
 }
 
 li:last-child {
@@ -93,7 +144,7 @@ li a {
 }
 
 li a:hover {
-    background-color: #f8f9fa;
+    background-color: var(--hover-bg);
     transform: translateX(5px);
     transition: all 0.2s ease;
 }
@@ -107,7 +158,7 @@ li a:hover {
 }
 
 .back-btn {
-    background-color: #95a5a6;
+    background-color: var(--muted);
     color: white;
     border: none;
     padding: 10px 20px;
@@ -119,30 +170,32 @@ li a:hover {
 }
 
 .back-btn:hover {
-    background-color: #7f8c8d;
+    background-color: var(--muted-hover);
 }
 
 .problem-desc {
-    background: white;
+    background: var(--card);
     padding: 30px;
     border-radius: 8px;
-    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
+    box-shadow: var(--shadow);
     margin-bottom: 30px;
     font-size: 1.1em;
     line-height: 1.7;
+    transition: background-color 0.3s ease;
 }
 
 /* Editor section */
 .editor-section {
-    background: white;
+    background: var(--card);
     padding: 30px;
     border-radius: 8px;
-    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
+    box-shadow: var(--shadow);
     margin-bottom: 30px;
+    transition: background-color 0.3s ease;
 }
 
 #editor {
-    border: 2px solid #ddd;
+    border: 2px solid var(--border);
     border-radius: 8px;
     margin: 20px 0;
     height: 400px;
@@ -155,7 +208,7 @@ li a:hover {
 }
 
 form button[type="submit"] {
-    background-color: #27ae60;
+    background-color: var(--success);
     color: white;
     border: none;
     padding: 12px 30px;
@@ -167,50 +220,52 @@ form button[type="submit"] {
 }
 
 form button[type="submit"]:hover {
-    background-color: #229954;
+    background-color: var(--success-hover);
 }
 
 /* Results section */
 b {
-    color: #2c3e50;
+    color: var(--heading);
     display: inline-block;
     margin: 10px 0 5px 0;
 }
 
 pre {
-    background-color: #f4f4f4;
+    background-color: var(--code-bg);
     padding: 20px;
     border-radius: 6px;
-    border-left: 4px solid #3498db;
+    border-left: 4px solid var(--accent);
     margin: 10px 0 20px 0;
     overflow-x: auto;
-    font-family: 'JetBrains Mono', 'Courier New', monospace;
+    font-family: "JetBrains Mono", "Courier New", monospace;
     font-size: 14px;
     line-height: 1.4;
+    border: 1px solid var(--border);
+    transition: background-color 0.3s ease;
 }
 
 pre[style*="color:red"] {
-    border-left-color: #e74c3c;
+    border-left-color: var(--error);
-    background-color: #fdf2f2;
+    background-color: var(--error-bg);
 }
 
 /* Status messages */
 p[style*="color:green"] {
-    background-color: #d4edda;
+    background-color: var(--success-bg);
-    color: #155724;
+    color: var(--success-text);
     padding: 15px 20px;
     border-radius: 6px;
-    border-left: 4px solid #27ae60;
+    border-left: 4px solid var(--success);
     margin: 20px 0;
     font-weight: 600;
 }
 
 p[style*="color:red"] {
-    background-color: #f8d7da;
+    background-color: var(--error-bg);
-    color: #721c24;
+    color: var(--error-text);
     padding: 15px 20px;
     border-radius: 6px;
-    border-left: 4px solid #e74c3c;
+    border-left: 4px solid var(--error);
     margin: 20px 0;
     font-weight: 600;
 }
@@ -219,7 +274,7 @@ p[style*="color:red"] {
 a[href="/"] {
     display: inline-block;
     margin-top: 30px;
-    background-color: #6c757d;
+    background-color: var(--muted);
     color: white;
     padding: 10px 20px;
     border-radius: 6px;
@@ -227,7 +282,7 @@ a[href="/"] {
 }
 
 a[href="/"]:hover {
-    background-color: #5a6268;
+    background-color: var(--muted-hover);
 }
 
 /* Responsive design */
@@ -246,7 +301,9 @@ a[href="/"]:hover {
         font-size: 1.8em;
     }
 
-    .problem-desc, .editor-section, ul {
+    .problem-desc,
+    .editor-section,
+    ul {
         padding: 20px;
     }
 

src/templates/index.html

@@ -1,62 +1,79 @@
 <!doctype html>
-<html lang="en">
+<html lang="en" class="">
 <head>
-  <meta charset="utf-8" />
+<meta charset="utf-8" />
-  <meta name="viewport" content="width=device-width,initial-scale=1" />
+<meta name="viewport" content="width=device-width,initial-scale=1" />
-  <title>Quick Problem Platform</title>
+<title>Quick Problem Platform</title>
-  <!--<link rel="favicon" href="/favicon/favicon.ico">-->
+<link rel="icon" type="image/x-icon" href="{{ url_for('static', filename='favicon.ico') }}">
-  <script src="script.js" async defer></script>
+<link rel="stylesheet" href="{{ url_for('static', filename='index.css') }}">
-  <link rel="stylesheet" href="/static/index.css">
+</head>
+<style>
+/* Popout explanation */
+#rankingExplanation {
+  grid-column: 1 / span 2;
+  max-height: 0;
+  opacity: 0;
+  overflow: hidden;
+  transition: max-height 0.5s ease, opacity 0.4s ease, padding 0.4s ease;
+  padding: 0 12px;
+}
+#rankingExplanation.active {
+  max-height: 800px;
+  opacity: 1;
+  padding: 12px;
+}
+#rankInfoBtn.active { color: #2563eb; cursor:pointer; transition: transform 0.3s ease; }
+#rankInfoBtn.active { transform: rotate(90deg); }
 
+/* Highlight top rank */
+.rank-1 td:first-child { font-weight: bold; }
+.sort-asc::after { content: " ↑"; }
+.sort-desc::after { content: " ↓"; }
+</style>
 </head>
 <body>
 <div class="wrap">
   <header>
-    <h1>Quick Problem Platform</h1>
+    <div class="header-content">
+      <h1>Quick Problem Platform</h1>
+      <button id="darkModeToggle" class="dark-mode-toggle" title="Toggle dark mode">
+        <span class="dark-mode-icon"></span>
+      </button>
+    </div>
   </header>
   <div class="content" id="contentContainer">
     <!-- Problems -->
-<section class="card problems-list">
+    <section class="card problems-list">
-  <div class="search-controls">
+      <div class="search-controls">
-    <input 
+        <input type="text" class="search-input" id="problemSearch" placeholder="Search problems..." />
-      type="text" 
-      class="search-input" 
-      id="problemSearch" 
-      placeholder="Search problems..." 
-    />
-  </div>
-  <h2 style="margin-bottom:6px;font-size:1.1rem">Problems</h2>
-  <div id="problemsContainer">
-    {% for folder, description, test_code, difficulty in problems %}
-      <div class="problem-item" data-name="{{ folder.replace('_',' ').title() }}" data-desc="{{ description }}">
-        <a href="/problem/{{ folder }}">{{ folder.replace('_',' ').title() }}</a>
-        <span class="difficulty" data-difficulty="{{ difficulty|lower }}">{{ difficulty }}</span>
       </div>
-    {% else %}
+      <h2 style="margin-bottom:6px;font-size:1.1rem">Problems</h2>
-      <div class="problem-item">No problems yet.</div>
+      <div id="problemsContainer">
-    {% endfor %}
+        {% for folder, description, test_code, difficulty in problems %}
-  </div>
+          <div class="problem-item" data-name="{{ folder.replace('_',' ').title() }}" data-desc="{{ description }}" data-difficulty="{{ difficulty|lower }}">
-</section>
+            <a href="/problem/{{ folder }}">{{ folder.replace('_',' ').title() }}</a>
+            <span class="difficulty" data-difficulty="{{ difficulty|lower }}">{{ difficulty }}</span>
+          </div>
+        {% else %}
+          <div class="problem-item">No problems yet.</div>
+        {% endfor %}
+      </div>
+      <div class="pagination-controls" id="problemsPagination">
+        <button class="pagination-btn" id="problemsPrevBtn" disabled>← Previous</button>
+        <span class="pagination-info" id="problemsPaginationInfo">Page 1 of 1</span>
+        <button class="pagination-btn" id="problemsNextBtn" disabled>Next →</button>
+      </div>
+    </section>
 
     <!-- Leaderboard -->
     <section class="card" id="leaderboardSection">
       <div class="leaderboard-head">
-        <h2 style="font-size:1.1rem;margin:0">Leaderboard</h2>
+        <h2 style="font-size:1.1rem;margin:0">Leaderboard
-        <button class="btn" id="toggleLeaderboard">Hide</button>
+          <span id="rankInfoBtn" title="How ranking works">ℹ️</span>
+        </h2>
       </div>
       <div class="leaderboard-controls">
-        <input 
+        <input type="text" class="search-input" id="problemFilter" placeholder="Filter by problem..." />
-          type="text" 
-          class="search-input" 
-          id="userSearch" 
-          placeholder="Filter by user..." 
-        />
-        <input 
-          type="text" 
-          class="search-input" 
-          id="problemFilter" 
-          placeholder="Filter by problem..." 
-        />
         <select class="filter-select" id="runtimeFilter">
           <option value="">All runtimes</option>
           <option value="best">Best runtime</option>
@@ -83,7 +100,14 @@
                 data-timestamp="{{ entry[5] }}">
               <td>{{ loop.index }}</td>
               <td>{{ entry[0] }}</td>
-              <td>{{ problem_titles.get(entry[1], 'Unknown') }}</td>
+              <td>
+                <a href="/problem/{{ problem_titles.get(entry[1], 'Unknown') }}"
+                  style="color:#2563eb; text-decoration: none;"
+                  onmouseover="this.style.textDecoration='underline';"
+                  onmouseout="this.style.textDecoration='none';">
+                  {{ problem_titles.get(entry[1], 'Unknown') }}
+                </a>
+              </td>
               <td>{{ '%.4f'|format(entry[2]) }}</td>
               <td>{{ entry[3] }}</td>
               <td>{{ entry[4] if entry[4] else '-' }}</td>
@@ -96,7 +120,27 @@
         </table>
       </div>
     </section>
+
+    <!-- Ranking explanation -->
+    <section class="card" id="rankingExplanation">
+      <h2 style="font-size:1.1rem;margin-bottom:6px">How Ranking Works</h2>
+      <p>The leaderboard uses a <strong>weighted scoring system</strong> to determine overall rank:</p>
+      <ul style="margin-left: 15px;">
+        <li><strong>Runtime:</strong> How fast the solution runs (lower is better).</li>
+        <li><strong>Memory Usage:</strong> How much memory the solution uses (lower is better).</li>
+      </ul>
+      <p>Overall score is calculated as:</p>
+      <div style="background:#f9f9f9; border-left:4px solid #007acc; padding:1rem; margin:1rem 0;">
+        <code>
+          runtimeScore = yourRuntime / bestRuntime<br>
+          memoryScore  = yourMemory / bestMemory<br>
+          overallScore = runtimeScore × 0.7 + memoryScore × 0.3
+        </code>
+      </div>
+      <p>Lower overall scores are better. If scores are equal, earlier submission ranks higher.</p>
+    </section>
   </div>
 </div>
+<script src="{{ url_for('static', filename='script.js') }}"></script>
 </body>
 </html>

src/templates/problem.html

@@ -1,296 +1,158 @@
-<!DOCTYPE html>
+<!doctype html>
-<html lang="en">
+<html lang="en" class="">
-<head>
+    <head>
-    <meta charset="UTF-8">
+        <meta charset="UTF-8" />
-    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+        <meta name="viewport" content="width=device-width, initial-scale=1.0" />
-    <title>{{ problem.title }} - Coding Problem</title>
+        <title>{{ problem.title }} - Coding Problem</title>
-    <link rel="stylesheet" href="/static/style.css">
+        <link rel="stylesheet" href="/static/style.css" />
-    <link href="https://fonts.cdnfonts.com/css/jetbrains-mono" rel="stylesheet">
+        <link rel="stylesheet" href="/static/problem.css" />
-    <link href="https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600&display=swap" rel="stylesheet">
+        <!-- this is stoopid fucking html link for favicon. just cause of flask-->
-    <style>
+        <link
-        body {
+            rel="icon"
-    font-family: 'Inter', sans-serif;
+            type="image/x-icon"
-    margin: 0;
+            href="{{ url_for('static', filename='favicon.ico') }}"
-    padding: 0;
+        />
-    background-color: #f9f9f9;
+        <link
-    color: #333;
+            href="https://fonts.cdnfonts.com/css/jetbrains-mono"
-    min-height: 100vh; /* allow content to grow */
+            rel="stylesheet"
-    overflow-y: auto;  /* allow vertical scroll */
+        />
-    box-sizing: border-box;
+        <link
-}
+            href="https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600&display=swap"
-*, *::before, *::after {
+            rel="stylesheet"
-    box-sizing: inherit;
+        />
-}
+    </head>
-
+    <body>
-.main-container {
+        <div class="main-container">
-    display: flex;
+            <div class="problem-panel">
-    flex-wrap: wrap; /* wrap on small screens */
+                <div class="problem-header">
-    min-height: 100vh;
+                    <button class="back-btn" onclick="window.location.href='/'">
-    width: 100vw;
+                        ← Back
-}
+                    </button>
-
+                    <h1>{{ problem.title }}</h1>
-.problem-panel {
+                    <button
-    flex: 1 1 400px; /* grow/shrink with base 400px */
+                        id="darkModeToggle"
-    min-width: 300px;
+                        class="dark-mode-toggle"
-    background: white;
+                        title="Toggle dark mode"
-    overflow-y: auto;
+                    >
-    padding: 20px;
+                        <span class="dark-mode-icon"></span>
-    border-right: 1px solid #eaeaea;
+                    </button>
-    max-height: 100vh;
+                </div>
-}
+                <div class="problem-desc">
-
+                    {{ problem.description | safe | markdown }}
-.editor-container {
+                </div>
-    flex: 1 1 400px;
-    min-width: 300px;
-    display: flex;
-    flex-direction: column;
-    background: white;
-    max-height: 100vh;
-    overflow: hidden; /* internal scroll handling */
-}
-
-.editor-header {
-    padding: 15px 20px;
-    border-bottom: 1px solid #eaeaea;
-    flex-shrink: 0;
-}
-
-.editor-wrapper {
-    flex: 1 1 auto;
-    display: flex;
-    flex-direction: column;
-    min-height: 0;
-    padding: 0 20px;
-    overflow-y: auto;
-}
-
-.problem-header {
-    display: flex;
-    align-items: center;
-    margin-bottom: 20px;
-}
-
-.back-btn {
-    background: none;
-    border: none;
-    cursor: pointer;
-    font-size: 16px;
-    color: #666;
-    margin-right: 15px;
-    padding: 5px;
-}
-
-.back-btn:hover {
-    color: #000;
-}
-
-h1 {
-    font-size: 22px;
-    font-weight: 600;
-    margin: 0;
-    color: #1a1a1a;
-}
-
-.problem-desc {
-    line-height: 1.6;
-    font-size: 15px;
-    overflow-wrap: break-word;
-}
-
-.problem-desc pre {
-    background: #f6f8fa;
-    padding: 12px;
-    border-radius: 4px;
-    overflow-x: auto;
-    font-family: 'JetBrains Mono', monospace;
-    font-size: 14px;
-}
-
-.problem-desc code {
-    background: #f6f8fa;
-    padding: 2px 4px;
-    border-radius: 3px;
-    font-family: 'JetBrains Mono', monospace;
-    font-size: 14px;
-}
-
-.editor-actions {
-    padding: 15px 0;
-    display: flex;
-    justify-content: flex-end;
-    flex-shrink: 0;
-}
-
-.editor-actions button {
-    background-color: #007bff;
-    color: white;
-    border: none;
-    padding: 8px 16px;
-    border-radius: 4px;
-    cursor: pointer;
-    font-weight: 500;
-    font-size: 14px;
-}
-
-.editor-actions button:hover {
-    background-color: #0069d9;
-}
-
-#editor {
-    flex: 1 1 auto;
-    min-height: 300px;
-    border: 1px solid #ddd;
-    border-radius: 4px;
-    overflow: auto;
-    max-height: 60vh;
-}
-
-.result-panel {
-    margin-top: 20px;
-    padding: 15px;
-    background: #f8f9fa;
-    border-radius: 4px;
-    margin-bottom: 20px;
-    min-height: 120px;
-    overflow-y: auto;
-    max-height: 30vh;
-}
-
-.result-panel h3 {
-    margin-top: 0;
-    font-size: 16px;
-    margin-bottom: 10px;
-}
-
-.result-panel pre {
-    background: #f6f8fa;
-    padding: 12px;
-    border-radius: 4px;
-    overflow-x: auto;
-    white-space: pre-wrap;
-    font-family: 'JetBrains Mono', monospace;
-    font-size: 14px;
-    margin: 5px 0;
-}
-
-.placeholder {
-    color: #999;
-    font-style: italic;
-    text-align: center;
-    padding: 20px;
-}
-
-label {
-    display: block;
-    margin-bottom: 5px;
-    font-size: 14px;
-    color: #666;
-}
-
-input[type="text"] {
-    width: 100%;
-    padding: 8px;
-    border: 1px solid #ddd;
-    border-radius: 4px;
-    margin-bottom: 15px;
-    font-family: 'Inter', sans-serif;
-}
-
-/* Responsive adjustments */
-@media (max-width: 768px) {
-    .main-container {
-        flex-direction: column;
-        height: auto;
-        overflow-y: visible;
-    }
-    .problem-panel, .editor-container {
-        flex: none;
-        width: 100%;
-        min-width: auto;
-        max-height: none;
-        border-right: none;
-        border-bottom: 1px solid #eaeaea;
-    }
-    #editor {
-        min-height: 400px;
-        max-height: none;
-    }
-    .result-panel {
-        max-height: none;
-    }
-}
-
-    </style>
-</head>
-<body>
-    <div class="main-container">
-        <div class="problem-panel">
-            <div class="problem-header">
-                <button class="back-btn" onclick="window.location.href='/'">← Back</button>
-                <h1>{{ problem.title }}</h1>
             </div>
-            <div class="problem-desc">{{ problem.description | safe | markdown }}</div>
-        </div>
 
-        <div class="editor-container">
+            <div class="editor-container">
-            <div class="editor-header">
+                <div class="editor-header">
-                <h2 style="margin:0;font-size:18px;">Submit Your Solution (Python)</h2>
+                    <h2 style="margin: 0; font-size: 18px">
-            </div>
+                        Submit Your Solution (Python)
-            <div class="editor-wrapper">
+                    </h2>
-                <form method="post">
+                </div>
-                    <label for="username">Username (optional):</label>
+                <div class="editor-wrapper">
-                    <input type="text" name="username" id="username" placeholder="Anonymous">
+                    <form method="post">
-                    <div id="editor"></div>
+                        <label for="username">Username (optional):</label>
-                    <textarea name="user_code" id="user_code" style="display:none;"></textarea>
+                        <input
-                    <div class="editor-actions">
+                            type="text"
-                        <button type="submit">Run & Submit</button>
+                            name="username"
-                    </div>
+                            id="username"
-                </form>
+                            placeholder="Anonymous"
+                        />
+                        <div id="editor"></div>
+                        <textarea
+                            name="user_code"
+                            id="user_code"
+                            style="display: none"
+                        ></textarea>
+                        <div class="editor-actions">
+                            <button type="submit">Run & Submit</button>
+                        </div>
+                    </form>
 
-                <div class="result-panel">
+                    <div class="result-panel">
-                    <h3>Result</h3>
+                        <h3>Result</h3>
-                    {% if result %}
+                        {% if result %}
-                        <p><b>Runtime:</b> {{ '%.4f'|format(result.runtime) }} seconds</p>
+                        <p>
+                            <b>Runtime:</b> {{ '%.4f'|format(result.runtime) }}
+                            seconds
+                        </p>
                         <p><b>Output:</b></p>
                         <pre>{{ result.output }}</pre>
                         {% if result.error %}
-                            <p><b>Error:</b></p>
+                        <p><b>Error:</b></p>
-                            <pre>{{ result.error }}</pre>
+                        <pre>{{ result.error }}</pre>
-                        {% endif %}
+                        {% endif %} {% else %}
-                    {% else %}
                         <div class="placeholder">
                             Your code execution results will appear here
                         </div>
-                    {% endif %}
+                        {% endif %}
+                    </div>
                 </div>
             </div>
         </div>
-    </div>
 
-    <script src="https://cdn.jsdelivr.net/npm/monaco-editor@0.45.0/min/vs/loader.js"></script>
+        <script src="https://cdn.jsdelivr.net/npm/monaco-editor@0.45.0/min/vs/loader.js"></script>
-    <script>
+        <script>
-      require.config({ paths: { 'vs': 'https://cdn.jsdelivr.net/npm/monaco-editor@0.45.0/min/vs' } });
+            // Dark mode functionality
-      require(['vs/editor/editor.main'], function() {
+            const darkModeToggle = document.getElementById("darkModeToggle");
-        var editor = monaco.editor.create(document.getElementById('editor'), {
+            const html = document.documentElement;
-          value: '',
+
-          language: 'python',
+            // Load saved dark mode preference
-          theme: 'vs-light',
+            const savedDarkMode = localStorage.getItem("darkMode");
-          fontFamily: 'JetBrains Mono, monospace',
+            if (
-          fontLigatures: true,
+                savedDarkMode === "true" ||
-          automaticLayout: true,
+                (savedDarkMode === null &&
-          fontSize: 16,
+                    window.matchMedia("(prefers-color-scheme: dark)").matches)
-          minimap: { enabled: false }
+            ) {
-        });
+                html.classList.add("dark");
-        document.querySelector('form').addEventListener('submit', function(e) {
+            }
-          var code = editor.getValue();
+
-          if (!code.trim()) {
+            darkModeToggle.addEventListener("click", () => {
-            alert('Please enter your code before submitting.');
+                html.classList.toggle("dark");
-            e.preventDefault();
+                localStorage.setItem(
-            return false;
+                    "darkMode",
-          }
+                    html.classList.contains("dark"),
-          document.getElementById('user_code').value = code;
+                );
-        });
+                // Update Monaco editor theme
-      });
+                if (window.monacoEditor) {
-    </script>
+                    const isDark = html.classList.contains("dark");
-</body>
+                    window.monacoEditor.updateOptions({
+                        theme: isDark ? "vs-dark" : "vs-light",
+                    });
+                }
+            });
+
+            require.config({
+                paths: {
+                    vs: "https://cdn.jsdelivr.net/npm/monaco-editor@0.45.0/min/vs",
+                },
+            });
+            require(["vs/editor/editor.main"], function () {
+                const isDark = html.classList.contains("dark");
+                window.monacoEditor = monaco.editor.create(
+                    document.getElementById("editor"),
+                    {
+                        value: "",
+                        language: "python",
+                        theme: isDark ? "vs-dark" : "vs-light",
+                        fontFamily: "JetBrains Mono, monospace",
+                        fontLigatures: true,
+                        automaticLayout: true,
+                        fontSize: 16,
+                        minimap: { enabled: false },
+                    },
+                );
+                document
+                    .querySelector("form")
+                    .addEventListener("submit", function (e) {
+                        var code = window.monacoEditor.getValue();
+                        if (!code.trim()) {
+                            alert("Please enter your code before submitting.");
+                            e.preventDefault();
+                            return false;
+                        }
+                        document.getElementById("user_code").value = code;
+                    });
+            });
+        </script>
+    </body>
 </html>

src/templates/script.js

@@ -1,152 +0,0 @@
-// Toggle leaderboard visibility
-const toggleBtn = document.getElementById('toggleLeaderboard');
-const leaderboardSection = document.getElementById('leaderboardSection');
-const contentContainer = document.getElementById('contentContainer');
-
-toggleBtn.addEventListener('click', () => {
-if (leaderboardSection.style.display === 'none') {
-    leaderboardSection.style.display = '';
-    toggleBtn.textContent = 'Hide';
-    contentContainer.classList.remove('single-column');
-} else {
-    leaderboardSection.style.display = 'none';
-    toggleBtn.textContent = 'Show';
-    contentContainer.classList.add('single-column');
-}
-});
-
-// Problem search functionality
-const problemSearch = document.getElementById('problemSearch');
-const problemsContainer = document.getElementById('problemsContainer');
-const problemItems = problemsContainer.querySelectorAll('.problem-item');
-
-problemSearch.addEventListener('input', () => {
-const searchTerm = problemSearch.value.toLowerCase();
-problemItems.forEach(item => {
-    const name = item.dataset.name.toLowerCase();
-    const desc = item.dataset.desc?.toLowerCase() || '';
-    if (name.includes(searchTerm) || desc.includes(searchTerm)) {
-    item.style.display = '';
-    } else {
-    item.style.display = 'none';
-    }
-});
-});
-
-// Leaderboard filtering and sorting
-const userSearch = document.getElementById('userSearch');
-const problemFilter = document.getElementById('problemFilter');
-const runtimeFilter = document.getElementById('runtimeFilter');
-const leaderboardBody = document.getElementById('leaderboardBody');
-const leaderboardRows = Array.from(leaderboardBody.querySelectorAll('tr'));
-const sortableHeaders = document.querySelectorAll('.sortable');
-
-// Current sort state
-let currentSort = {
-column: null,
-direction: 'asc'
-};
-
-// Filter leaderboard
-function filterLeaderboard() {
-const userTerm = userSearch.value.toLowerCase();
-const problemTerm = problemFilter.value.toLowerCase();
-const runtimeType = runtimeFilter.value;
-
-leaderboardRows.forEach(row => {
-    const user = row.dataset.user.toLowerCase();
-    const problem = row.dataset.problem.toLowerCase();
-    const runtime = parseFloat(row.dataset.runtime);
-    const showUser = user.includes(userTerm);
-    const showProblem = problem.includes(problemTerm);
-    
-    let showRuntime = true;
-    if (runtimeType === 'best') {
-    // Find if this is the best runtime for this user+problem combo
-    const userProblemRows = leaderboardRows.filter(r => 
-        r.dataset.user === row.dataset.user && 
-        r.dataset.problem === row.dataset.problem
-    );
-    const bestRuntime = Math.min(...userProblemRows.map(r => parseFloat(r.dataset.runtime)));
-    showRuntime = runtime === bestRuntime;
-    } else if (runtimeType === 'worst') {
-    // Find if this is the worst runtime for this user+problem combo
-    const userProblemRows = leaderboardRows.filter(r => 
-        r.dataset.user === row.dataset.user && 
-        r.dataset.problem === row.dataset.problem
-    );
-    const worstRuntime = Math.max(...userProblemRows.map(r => parseFloat(r.dataset.runtime)));
-    showRuntime = runtime === worstRuntime;
-    }
-
-    if (showUser && showProblem && showRuntime) {
-    row.style.display = '';
-    } else {
-    row.style.display = 'none';
-    }
-});
-}
-
-// Sort leaderboard
-function sortLeaderboard(column, direction) {
-const rows = Array.from(leaderboardBody.querySelectorAll('tr'));
-const index = Array.from(document.querySelectorAll('th')).findIndex(th => th.dataset.sort === column);
-
-rows.sort((a, b) => {
-    let aValue = a.cells[index].textContent;
-    let bValue = b.cells[index].textContent;
-    
-    // Special handling for numeric columns
-    if (column === 'runtime' || column === 'memory' || column === 'rank') {
-    aValue = parseFloat(aValue) || 0;
-    bValue = parseFloat(bValue) || 0;
-    return direction === 'asc' ? aValue - bValue : bValue - aValue;
-    }
-    
-    // Special handling for timestamps
-    if (column === 'timestamp') {
-    aValue = new Date(aValue).getTime();
-    bValue = new Date(bValue).getTime();
-    return direction === 'asc' ? aValue - bValue : bValue - aValue;
-    }
-    
-    // Default string comparison
-    aValue = aValue.toLowerCase();
-    bValue = bValue.toLowerCase();
-    if (aValue < bValue) return direction === 'asc' ? -1 : 1;
-    if (aValue > bValue) return direction === 'asc' ? 1 : -1;
-    return 0;
-});
-
-// Re-append rows in sorted order
-rows.forEach(row => leaderboardBody.appendChild(row));
-}
-
-// Set up event listeners
-userSearch.addEventListener('input', filterLeaderboard);
-problemFilter.addEventListener('input', filterLeaderboard);
-runtimeFilter.addEventListener('change', filterLeaderboard);
-
-// Set up sorting
-sortableHeaders.forEach(header => {
-header.addEventListener('click', () => {
-    const column = header.dataset.sort;
-    
-    // Reset all sort indicators
-    sortableHeaders.forEach(h => {
-    h.classList.remove('sort-asc', 'sort-desc');
-    });
-    
-    // Determine new sort direction
-    if (currentSort.column === column) {
-    currentSort.direction = currentSort.direction === 'asc' ? 'desc' : 'asc';
-    } else {
-    currentSort.column = column;
-    currentSort.direction = 'asc';
-    }
-    
-    // Apply new sort
-    header.classList.add(`sort-${currentSort.direction}`);
-    sortLeaderboard(column, currentSort.direction);
-});
-});

src/utils.py

@@ -5,8 +5,127 @@ import io
 import tempfile
 import subprocess
 import os
+import re
+import ast
+
+# Security configuration
+ALLOWED_IMPORTS = {
+    'math', 'random', 'datetime', 'json', 'collections', 'itertools',
+    'functools', 'operator', 'copy', 'unittest', 're', 'string'
+}
+
+DANGEROUS_PATTERNS = [
+    r'import\s+os(?:\s|$|\.)',
+    r'from\s+os\s+import',
+    r'import\s+subprocess(?:\s|$|\.)',
+    r'from\s+subprocess\s+import',
+    r'import\s+sys(?:\s|$|\.)',
+    r'from\s+sys\s+import',
+    r'import\s+shutil(?:\s|$|\.)',
+    r'from\s+shutil\s+import',
+    r'import\s+pathlib(?:\s|$|\.)',
+    r'from\s+pathlib\s+import',
+    r'__import__\s*\(',
+    r'exec\s*\(',
+    r'eval\s*\(',
+    r'compile\s*\(',
+    r'open\s*\(',
+    r'file\s*\(',
+    r'input\s*\(',
+    r'raw_input\s*\(',
+    r'\.unlink\s*\(',
+    r'\.remove\s*\(',
+    r'\.rmdir\s*\(',
+    r'\.rmtree\s*\(',
+    r'\.delete\s*\(',
+    r'\.kill\s*\(',
+    r'\.terminate\s*\(',
+]
+
+def validate_code_security(code):
+    """
+    Validates code for security issues.
+    Returns (is_safe, error_message)
+    """
+    # Check for dangerous patterns
+    for pattern in DANGEROUS_PATTERNS:
+        if re.search(pattern, code, re.IGNORECASE):
+            return False, f"Dangerous operation detected: {pattern}"
+    
+    # Parse AST to check imports
+    try:
+        tree = ast.parse(code)
+        for node in ast.walk(tree):
+            if isinstance(node, ast.Import):
+                for alias in node.names:
+                    module_name = alias.name.split('.')[0]
+                    if module_name not in ALLOWED_IMPORTS:
+                        return False, f"Import not allowed: {module_name}"
+            elif isinstance(node, ast.ImportFrom):
+                if node.module:
+                    module_name = node.module.split('.')[0]
+                    if module_name not in ALLOWED_IMPORTS:
+                        return False, f"Import not allowed: {module_name}"
+    except SyntaxError as e:
+        return False, f"Syntax error in code: {str(e)}"
+    
+    return True, None
+
+def create_restricted_globals():
+    """Create a restricted global namespace for code execution."""
+    safe_builtins = {
+        'abs', 'all', 'any', 'bin', 'bool', 'chr', 'dict', 'dir', 
+        'divmod', 'enumerate', 'filter', 'float', 'format', 'frozenset',
+        'hex', 'id', 'int', 'isinstance', 'issubclass', 'iter', 'len',
+        'list', 'map', 'max', 'min', 'next', 'oct', 'ord', 'pow',
+        'print', 'range', 'repr', 'reversed', 'round', 'set', 'slice',
+        'sorted', 'str', 'sum', 'tuple', 'type', 'zip'
+    }
+    
+    restricted_globals = {
+        '__builtins__': {name: __builtins__[name] for name in safe_builtins if name in __builtins__}
+    }
+    
+    # Add allowed modules
+    for module in ALLOWED_IMPORTS:
+        try:
+            restricted_globals[module] = __import__(module)
+        except ImportError:
+            pass  # Module not available
+    
+    return restricted_globals
+
+def run_code_against_tests(user_code, test_code, max_execution_time=5):
+    """
+    Securely run user code against test code with safety restrictions.
+    
+    Args:
+        user_code: The user's solution code
+        test_code: The test code to validate the solution
+        max_execution_time: Maximum execution time in seconds (default: 5)
+    
+    Returns:
+        dict: Result containing passed, output, runtime, and error information
+    """
+    # Validate security for both user code and test code
+    user_safe, user_error = validate_code_security(user_code)
+    if not user_safe:
+        return {
+            'passed': False,
+            'output': '',
+            'runtime': 0,
+            'error': f"Security violation in user code: {user_error}"
+        }
+    
+    test_safe, test_error = validate_code_security(test_code)
+    if not test_safe:
+        return {
+            'passed': False,
+            'output': '',
+            'runtime': 0,
+            'error': f"Security violation in test code: {test_error}"
+        }
     
-def run_code_against_tests(user_code, test_code):
     local_ns = {}
     output = ''
     start = time.perf_counter()
@@ -17,60 +136,83 @@ def run_code_against_tests(user_code, test_code):
     try:
         # Check if unittest is used in test_code
         if 'unittest' in test_code:
-            # Write user code + test code to a temp file
+            # Create temp file in a secure temporary directory
-            with tempfile.NamedTemporaryFile('w+', suffix='.py', delete=False, encoding='utf-8') as f:
+            temp_dir = tempfile.mkdtemp(prefix='secure_code_')
-                combined_code = f"{user_code}\n\n{test_code}"
-                f.write(combined_code)
-                f.flush()
-                temp_file = f.name
-            
-            # Run the file as a subprocess
             try:
-                proc = subprocess.run(
+                temp_file = os.path.join(temp_dir, 'test_code.py')
-                    [sys.executable, temp_file], 
+                combined_code = f"{user_code}\n\n{test_code}"
-                    capture_output=True, 
-                    text=True, 
-                    timeout=10,
-                    encoding='utf-8'
-                )
-                output = proc.stdout
-                if proc.stderr:
-                    output += f"\n{proc.stderr}"
                 
-                passed = proc.returncode == 0
+                # Write to temp file with restricted permissions
-                if not passed:
+                with open(temp_file, 'w', encoding='utf-8') as f:
-                    error = f"Tests failed. Return code: {proc.returncode}\n{output}"
+                    f.write(combined_code)
-                else:
+                os.chmod(temp_file, 0o600)  # Read/write for owner only
-                    # For successful unittest runs, the stderr contains the test results
-                    if proc.stderr and "OK" in proc.stderr:
-                        output = proc.stderr  # Use stderr as the main output for unittest
                 
-            except subprocess.TimeoutExpired:
+                # Run the file as a subprocess with additional security
-                passed = False
+                try:
-                error = "Code execution timed out after 10 seconds"
+                    proc = subprocess.run(
-                output = "Execution timed out"
+                        [sys.executable, temp_file],
+                        capture_output=True,
+                        text=True,
+                        timeout=max_execution_time,
+                        encoding='utf-8',
+                        cwd=temp_dir,  # Run in the temporary directory
+                        env={'PYTHONPATH': ''}  # Restrict Python path
+                    )
                     
+                    # Combine both stdout and stderr to capture all output
+                    combined_output = ""
+                    if proc.stdout:
+                        combined_output += proc.stdout
+                    if proc.stderr:
+                        if combined_output:
+                            combined_output += "\n" + proc.stderr
+                        else:
+                            combined_output = proc.stderr
+                    
+                    output = combined_output
+                    passed = proc.returncode == 0
+                    
+                    if not passed:
+                        error = f"Tests failed. Return code: {proc.returncode}\n{output}"
+                            
+                except subprocess.TimeoutExpired:
+                    passed = False
+                    error = f"Code execution timed out after {max_execution_time} seconds"
+                    output = "Execution timed out"
+                    
+            finally:
+                # Secure cleanup of temporary directory and files
+                try:
+                    if temp_file and os.path.exists(temp_file):
+                        os.chmod(temp_file, 0o600)  # Ensure we can delete
+                        os.unlink(temp_file)
+                    if os.path.exists(temp_dir):
+                        os.rmdir(temp_dir)
+                except Exception as cleanup_error:
+                    print(f"Warning: Could not clean up temp files: {cleanup_error}")
         else:
-            # Capture stdout
+            # Direct execution with restricted globals
             old_stdout = sys.stdout
             captured_output = io.StringIO()
             sys.stdout = captured_output
             
             try:
-                # Execute user code
+                # Create restricted execution environment
-                exec(user_code, {}, local_ns)
+                restricted_globals = create_restricted_globals()
+                
+                # Execute user code in restricted environment
+                exec(user_code, restricted_globals, local_ns)
+                
                 # Execute test code (should raise AssertionError if fail)
-                exec(test_code, local_ns, local_ns)
+                exec(test_code, {**restricted_globals, **local_ns}, local_ns)
                 passed = True
                 
             except AssertionError as e:
                 passed = False
                 error = f"Assertion failed: {str(e)}"
-                
             except Exception as e:
                 passed = False
                 error = f"Runtime error: {traceback.format_exc()}"
-                
             finally:
                 output = captured_output.getvalue()
                 sys.stdout = old_stdout
@@ -79,16 +221,13 @@ def run_code_against_tests(user_code, test_code):
         passed = False
         error = f"Execution error: {traceback.format_exc()}"
     
-    finally:
-        # Clean up temporary file
-        if temp_file and os.path.exists(temp_file):
-            try:
-                os.unlink(temp_file)
-            except Exception as e:
-                print(f"Warning: Could not delete temp file {temp_file}: {e}")
-    
     runtime = time.perf_counter() - start
     
+    # Limit output size to prevent memory issues
+    max_output_size = 10000  # 10KB limit
+    if len(output) > max_output_size:
+        output = output[:max_output_size] + "\n... (output truncated)"
+    
     result = {
         'passed': passed,
         'output': output.strip() if output else '',
@@ -97,3 +236,27 @@ def run_code_against_tests(user_code, test_code):
     }
     
     return result
+
+# Example usage with additional safety wrapper
+def safe_code_runner(user_code, test_code):
+    """
+    Additional wrapper for extra safety checks.
+    """
+    # Additional length checks
+    if len(user_code) > 50000:  # 50KB limit
+        return {
+            'passed': False,
+            'output': '',
+            'runtime': 0,
+            'error': "User code too large (maximum 50KB allowed)"
+        }
+    
+    if len(test_code) > 10000:  # 10KB limit for test code
+        return {
+            'passed': False,
+            'output': '',
+            'runtime': 0,
+            'error': "Test code too large (maximum 10KB allowed)"
+        }
+    
+    return run_code_against_tests(user_code, test_code)