[LintCode] 寻找缺失的数

class Solution {
public:
/**
* @param nums: a vector of integers
* @return: an integer
*/
int findMissing(vector<int> &nums) {
// write your code here
int n = nums.size();
int number = 0;
for (int i = 0; i <= n; i++)
number ^= i;
for (int i = 0; i < n; i++)
number ^= nums[i];
return number;
}
};