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.

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

Solution:

Missing element= 0+1+2+...+n- (Sum(nums[]);

   public int missingNumber(int[] nums) {  
     int sum=0;  
     for(int i=0;i<nums.length;i++){  
       sum=sum+i+1-nums[i];  
     }  
     return sum;  
   }