Single Number

Easy~10 min

Given a non-empty array of integers nums, every element appears exactly twice except for one. Find that single one.

You must implement a solution with O(1) extra space complexity.

Examples

Example 1
Input: nums = [2, 2, 1]
Output: 1
Explanation: 1 is the only element that does not appear twice.
Example 2
Input: nums = [4, 1, 2, 1, 2]
Output: 4
Explanation: 4 is the only element that does not appear twice.
Example 3
Input: nums = [1]
Output: 1
Explanation: There is only one element, so it is the single number.

Constraints

  • 1 <= nums.length <= 3 * 10^4
  • -3 * 10^4 <= nums[i] <= 3 * 10^4
  • Each element in the array appears exactly twice except for one element which appears exactly once.
  • Expected time complexity: O(n)
Code
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Output

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