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$ curl repovive.com/roadmaps/math-fundamentals/bit-manipulation/single-number-implementation

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$ curl repovive.com/roadmaps/math-fundamentals/bit-manipulation/single-number-implementation

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Single Number - Implementation - Bit Manipulation | Math Fundamentals | Repovive

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Math Fundamentals18 sections · 842 units13h total

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Single Number - Implementation

The code

Here's the complete solution:


function singleNumber(nums)
    result := 0
    for each num in nums
        result := result ^ num
    return result

Initialize result to 0 (the XOR identity). XOR every number in the array. Pairs cancel out, leaving only the unique number. Time: $O(n)$ . Space: $O(1)$ . No hash map, no sorting, just one pass with XOR.