leetcode 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

.

涉及到位操作：异或



code:

int missingNumber(vector<int>& nuts)
{
int res=0;
for (int i=0;i<nums.size();i++){
res^=nums[i]^i;
}
res^=nums.size();
return res;
}math 方法

int missingNumber(vector<int>& nums) {
int n=nums.size();
int total = n*(n+1)/2;
for (auto &x:nums){
total-=x;
}
return total;
}