Insert Operator (Recursion)

 Insert Operator (Recursion)

Problem Statement

You are given a sequence of numbers of size N. You have to find if there is a way to insert + or - operator in between the numbers so that the result equals K.

import java.io.*; // for handling input/output

import java.util.*; // contains Collections framework

// don't change the name of this class

// you can add inner classes if needed

class Main {

    public static int rec(long []arr,long sum,int i){

         System.out.println("sum = "+sum);

        if(i==arr.length){

            if(sum==0){

                return 0;

            }else{

                return 1;

            }

        }

        return rec(arr,sum-arr[i],i+1)*rec(arr,sum+arr[i],i+1);

    }

    public static void main (String[] args) {

                      // Your code here

                      Scanner sc = new Scanner(System.in);

                      int n = sc.nextInt();

                      long target = sc.nextLong();

                      long []arr = new long[n];

                      for(int i=0;i<n;i++){

                          arr[i] = sc.nextLong();

                      }

                      int sum=(rec(arr,target,0));

                      System.out.println("sum = "+sum);

                      if(sum==0){

                          System.out.println("YES");

                      }else

                      {

                          System.out.println("NO");

                      }

    }

}