Help me in solving MAKEALLEQUAL problem

help
,
1

My issue

Only 1 test case which is the final one is not passing. Can anybody find out the issue in the code ?

My code

#include <bits/stdc++.h>
using namespace std;

int main() {
	// your code goes here
	int t;
	cin>>t;
	
	while(t--){
	    
     long long n;
      float m;
       cin>>n>>m;
       
       long long a[n];
       for(int i=0;i<n;i++){
           cin>>a[i];
       }
	    float s=0;
	    sort(a,a+n);
	   for(int i=0;i<n;i++){
          
           s+=a[n-1]-a[i];
       }
       float q=(a[n-1]-a[0]);
	   cout<<max(q,ceil(s/m))<<endl;
	}
		return 0;
}

Problem Link: Make All Equal Practice Coding Problem - CodeChef