Section 1Understand Problem
Section 01
Understand the problem
Restate the problem precisely. Interviewers reward candidates who pause, define the contract, and name the guarantees before coding.
Problem statement
Given an integer array `nums` where every element appears three times except for one, which appears exactly once. Find the single element and return it. You must implement a solution with a linear runtime complexity and use only constant extra space.
Example
nums = [2,2,3,2] → 3
Constraints
1 ≤ nums.length ≤ 3 · 10⁴ · −2³¹ ≤ nums[i] ≤ 2³¹ − 1 · Each element in nums appears exactly three times except for one element which appears once
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