[Leet Code] Missing Number

Leetcode: https://leetcode.com/problems/missing-number/submissions/

Problem:

Given an array nums containing n distinct numbers in the range [0, n], return the only number in the range that is missing from the array.Follow up: Could you implement a solution using only O(1) extra space complexity and O(n) runtime complexity?

Example:

Input: nums = [3,0,1]
Output: 2
Explanation: n = 3 since there are 3 numbers, so all numbers are in the range [0,3]. 2 is the missing number in the…