136.LeetCode Single Number

Given an array of integers, every element appears twice except for one. Find the single one.

This problem seems simple, but requires linear time and does not consume extra space, it is necessary to use the C + + "or" operation, because the same number ^ operation is 0,0 and any number ^ operation obtained is that number.

int singlenumber (vector<int>& nums) {        int0;          for (int0;i< nums.size (); i++) {            ^= nums[i];        }         return result;    }

136.LeetCode Single Number