Single Number
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 a linear runtime complexity and use only constant extra space.
Example 1
Input
nums = [2,2,1]Output
1The number 1 is the only element that appears once.
Example 2
Input
nums = [4,1,2,1,2]Output
4The number 4 is the only element that appears once.
Constraints
1 <= nums.length <= 3 * 10^4-3 * 10^4 <= nums[i] <= 3 * 10^4- Each element in the array appears twice except for one element which appears only once.