하루의 쉼터

Question Given a non-empty array of integers nums, every element appears twice except for one. Find that single one. Follow up: Could you implement a solution with a linear runtime complexity and without using extra memory? 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 Constraints: 1