Missing Number

Source

• leetcode: 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.

Note:
Your algorithm should run in linear runtime complexity. Could you
implement it using only constant extra space complexity?

Java

public class Solution {
    public int missingNumber(int[] nums) {
        int total=0;
        for(int n : nums){
            total+=n;
        }

        int max=nums.length*(nums.length+1)/2;
        return max-total;
    }
}