1 class Solution {
 2 public:
 3     /**    
 4      * @param nums: a vector of integers
 5      * @return: an integer
 6      */
 7     int findMissing(vector<int> &nums) {
 8         // write your code here
 9         int n = nums.size();
10         int number = 0;
11         for (int i = 0; i <= n; i++)
12             number ^= i;
13         for (int i = 0; i < n; i++)
14             number ^= nums[i];
15         return number;
16     }
17 };