136. 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.

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14

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 * 104
  • -3 * 10^4 <= nums[i] <= 3 * 10^4
  • Each element in the array appears twice except for one element which appears only once.

Solution

 1
 2
 3
 4
 5
 6
 7
 8
 9
10

class Solution {
    public int singleNumber(int[] nums) {
        int single = 0;
        
        for (int num: nums) {
            single ^= num;
        }
        return single;
    }
}

Solved 2022-01-15