LeetCode 268. Missing Number

Description

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?

Code

class Solution {public:    int missingNumber(vector<int>& nums) {        int sum = nums.size()*(nums.size()+1)/2;        for (int i = 0;i < nums.size(); i++)            sum -= nums[i];        return sum;    }};

Appendix

• Link: https://leetcode.com/problems/missing-number/
• Run Time: 32ms