MissNo0toN_268

Leetcode - 268 

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.

my code---

class Solution {
    public int missingNumber(int[] nums) {
        int k = nums.length;
        int j=0,p=1;
        while(j<=k){
          for(int i=0;i<nums.length;i++){
           if(j==nums[i]){
              j++; p=0;
              break;
            }
            else
            p=1;
        }
            if(p==1)
            return j;
        }
        return 0;
    }
}

Optimised Code --
class Solution {
    public int missingNumber(int[] nums) {
       int n = nums.length;
       int sum = 0;
       for(int i=0;i<nums.length;i++){
        sum+=nums[i];
       }
       int expectedSum = (n*(n+1))/2; //6
       int missingNumber = expectedSum - sum; // 6 - 4
       return missingNumber;
    }
}