Numbers that appear only once

This question examines the nature of XOR

Knowledge point ： The same number is XOR 0, Because the other elements of this problem appear twice, you can pair XOR until there is only one XOR that appears only once

class Solution {
public:
    int singleNumber(vector<int>& nums) {
       for(int i=1;i<nums.size();i++){
           nums[0]^=nums[i];
       }
       return nums[0];
    }
};