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;}