Single Number — Rust Coding Problem
Difficulty: easy | Category: array
Problem Description
Given a non-empty array of integers `nums`, every element appears **twice** except for one. Find that single one. You must implement a solution with linear runtime complexity and use only constant extra space. Hint: XOR is your friend — `a ^ a = 0` and `a ^ 0 = a`, so XOR-ing all elements cancels duplicates.
Examples
Example 1
Input: nums = [2, 2, 1]
Output: 1
Example 2
Input: nums = [4, 1, 2, 1, 2]
Output: 4
Example 3
Input: nums = [1]
Output: 1