Leetcode 136. Single Number
Given an array where every element appears exactly twice except for one, return the element that appears only once. Achieve O(n) time and O(1) space — this is typically solved by XORing all numbers so matching pairs cancel out.
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Early December, 2024
Amazon
Mid-level
Find the unpaired number in an array of 2n+1 numbers where all other numbers are paired and adjacent
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