mediumNeetCode 150

Find the Duplicate Number

Find the duplicate number in an array of n+1 integers in range [1,n] Use O(1) space and don't modify the array Example: [1,3,4,2,2] => 2

Find the Duplicate Number rewards precision: narrowing the search space correctly is the whole game. Interviewers love it because it reveals your boundary precision and your edge-case discipline. Interviewers care more about airtight boundaries than speed here.

Arrays & HashingTwo PointersBinary SearchBit Manipulation

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