Every element of the integer array nums appears exactly twice, except for one element that appears once. Return that single element.
Aim for linear time and constant extra space.
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
Constraints
1 <= nums.length <= 3 * 10^4-3 * 10^4 <= nums[i] <= 3 * 10^4