Please help me to solve this problem related to Maths

general
1

Problem Link:- https://mycode.prepbytes.com/problems/maths/CHERRED

My Approach:-

  1. let A and B be the candies given to each person than we can say that
    a valid distribution will be xA+yB=c
  2. from A=0 to A=n we will equate the above equation than find a valid B and if
    (A+B<=n) than it will be a valid distribution.

My Code:-

#include <bits/stdc++.h>
using namespace std;
#define ll long long 
int main()
{
  //write your code here
  int t ; cin>>t; 
  for(int i=0;i<t;i++)
  { 
    
    ll count=0;
    ll n,c,x,y; cin>>n>>c>>x>>y; 
    
    for(int r=0;r<=n;r++)
    { 
      ll z=-1;
    
      if((c-x*r)<0)
        break;
      if((c-x*r)%y==0)
      {
        z=(c-x*r)/y;
      }
      if(z>=0)
      {
        if(r+z<=n)
        {
          count++;
         // cout<<r<<" "<<z<<endl;
        }
      }
    }
    
    cout<<count<<endl;
  }
  
  return 0;
}