Bit manipulation: XOR & masks

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Task

📝 **Task:** Write `single_number(nums)`. Print `single_number([4,1,2,1,2])`. Expected: 4

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💡 **Hint:** Re-read the theory if stuck.

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🎯write

Math: prime sieve + Euclidean GCD

🎯writeFREE

Two pointers: pair sum

🎯write

Two pointers: palindrome check

🤖predictFREE

Prerequisites — what you should know before this track

⚡predictFREE

Prerequisites — what you should know before this track

✏️ Write your code here

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📊 Result

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💬 Discussion