lec16_waystoN.cpp

https://www.geeksforgeeks.org/problems/ways-to-sum-to-n5759/1?utm_source=geeksforgeeks&utm_medium=article_practice_tab&utm_campaign=article_practice_tab


//{ Driver Code Starts
#include <bits/stdc++.h> 
using namespace std; 
  

// } Driver Code Ends
class Solution
{
    
    
  public:
  
  int way(int arr[] , int m , int sum)
  {
      
      if(sum == 0 ) return 1;
      if(sum <0) return 0 ;
      long long  ans = 0;
      for(int i =  0  ; i<m ; i++)
      {
          ans+= way(arr , m , sum - arr[i]);
      }
      return ans%1000000007;
  }
    // function to count the total  
    // number of ways to sum up to 'N' 
    int countWays(int arr[], int m, int N) 
    { 
      //code here.
      
      return way(arr , m , N);
    } 
    
};


//{ Driver Code Starts.

int main()
{
	int t;
	cin>>t;
	while(t--)
	    {
	        int m,n ;
	        cin>>m>>n;
	        int arr[m];
	        for(int i = 0;i<m;i++)
	            cin>>arr[i];
	        Solution ob;     
	        cout<<ob.countWays(arr,m,n)<<endl;
	    }
}
// } Driver Code Ends