Leetcode-268 Missing Number

#268. Missing Number

Given an array containing n distinct numbers taken from

0, 1, 2, ..., n

, find the one that is missing from the array.

For example,
Given nums =

[0, 1, 3]

return

2

.

Note:
Your algorithm should run in linear runtime complexity. Could you implement it using only constant extra space complexity?

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