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:
1 <= nums.length <= 3 * 104-3 * 104 <= nums[i] <= 3 * 104- Each element in the array appears twice except for one element which appears only once.
Solution
#include <vector>
using namespace std;
class Solution {
public:
int singleNumber(vector<int>& nums) {
int res = 0;
for (int num : nums) {
res ^= num;
}
return res;
}
};