[LeetCode] Missing Number

question:

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.

解题思路： the missing number is where nums[i] != i

int missingNumber(vector<int>& nums) {        int result = 0;        if(nums.size() == 1 && nums[0] == 1)            return 0;        if(nums.size() == 1)            return nums[0] + 1;        sort(nums.begin(), nums.end());            for(int i = 0; i < nums.size(); i++)        {            if(nums[i] != i)            {                result = i;                return result;            }        }        result = nums[nums.size() - 1] + 1;        return result;    }