LeetCode-in-All

136. Single Number

Easy

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: 1

Example 2:

Input: nums = [4,1,2,1,2]

Output: 4

Example 3:

Input: nums = [1]

Output: 1

Constraints:

Solution

#include <stdio.h>

int singleNumber(int* nums, int numsSize) {
    int res = 0;
    for (int i = 0; i < numsSize; i++) {
        res ^= nums[i];
    }
    return res;
}