Skip to main content
🔒 Preview mode. The first 15 Foundations lessons are free; this one is Pro. Start a 7-day trial to unlock the editor, AI hints and the rest of the curriculum. Card required, cancel any time in Dashboard.Start 7-day trial →
← CoursesInterview PrepModule 3 · Trees, Graphs, BFS/DFS · RecapBit manipulation: XOR & maskswrite43 / 104
+100 XP
Task
📝 **Task:** Write `single_number(nums)`. Print `single_number([4,1,2,1,2])`. Expected: 4 📋 Edit the starter code. Tests run automatically. 💡 **Hint:** Re-read the theory if stuck.
✏️ Write your code here
🐍
Loading Python...
One-time download (~1 MB). Then it runs instantly.
📊 Result
Press Run to see result...

💬 Discussion

Be the first to ask a question or share a tip.
Sign in to join the discussion. Reading is free.
Loading discussion…