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$ curl repovive.com/roadmaps/math-fundamentals/boolean-logic/single-number-implementation

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$ curl repovive.com/roadmaps/math-fundamentals/boolean-logic/single-number-implementation

Repovive

Single Number - Implementation - Boolean Logic | 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 XOR num
    return result

This runs in $O(n)$ time and $O(1)$ space. The XOR operator (boolean logic at the bit level) cancels duplicate pairs, isolating the unique element. XOR turns a hard problem into three lines of code.