Repeating and Missing Java

PROGRAM TO FIND REPEATING AND MISSING NUMBERS

import java.util.*;

  

class MAIN 

{

    static Vector<Integer> repeatedNumber(int[] A) 

    {

        int len = A.length;

        int Sum_N = (len * (len + 1)) / 2;

        int Sum_NSq = (len * (len + 1) * 

                         (2 * len + 1)) / 6;

        int missingNumber = 0, repeating = 0;

  

        for (int i = 0; i < A.length; i++) 

        {

            Sum_N -= A[i];

            Sum_NSq -= A[i] * A[i];

        }

  

        missingNumber = (Sum_N + Sum_NSq / 

                                 Sum_N) / 2;

        repeating = missingNumber - Sum_N;

        Vector<Integer> ans = new Vector<>();

        ans.add(repeating);

        ans.add(missingNumber);

        return ans;

    }

  

    // Driver Code

    public static void main(String[] args) 

    {

        int[] v = { 4, 3, 6, 2, 1, 6, 7 };

        Vector<Integer> res = repeatedNumber(v);

        for (int x : res) 

        {

            System.out.print(x + " ");

        }

    }

}

OUTPUT

6 5 

CREDITS: https://www.geeksforgeeks.org/find-a-repeating-and-a-missing-number/