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Day 14Easy
LeetCodeRelated practice
LeetCodeRelated practiceSingle Number
Bit-Manipulation (XOR)Solved Nov 11, 2025
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LeetCodeRelated practiceBit-Manipulation (XOR)Solved Nov 11, 2025
6 in the last 6 months
Community-reported company tags from leetcode-company-wise-problems (updated 2026-10-08). Bar shows how often each company asks it.
Problem
Given a non-empty array of integers, every element appears twice except for one. Find that single one. The solution must have linear runtime complexity and use only constant extra space.
Reading the solution first feels like progress, but it makes the next similar problem — and the interview version — much harder, because you skipped the part where you figure it out. Give it an honest 20–30 minutes. Stuck? Re-read the pattern, watch the concept video, or try the brute force first.
Hidden: approach · solution code
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