Help me in solving SAVEKONO problem

help
,
1

My issue

What is wrong with my code? It’s giving the correct answer on the given sample input but it fails somewhere when the online judge checks it.

My code

#include <iostream>
#include <set>
using namespace std;

int main() {
	// your code goes here
	int t;
	cin>>t;
	while(t--)
	{
	    multiset<int> A;
	    int temp,N,Z;
	    cin>>N>>Z;
	    for (int i = 0; i < N; i++) {
	        cin>>temp;
	        A.insert(temp);
	    }
	    int attacks=0;
	    for(auto it=A.rbegin();it!=A.rend();++it){
	        if(Z<=0)
	        break;
	        else
	        {
	           // cout<<"Z="<<Z<<" ";
	            int X=*it;
	            Z=Z-X;
	            A.erase(X);
	            A.insert(X/2);
	            attacks++;
	        }
	    }
	    cout<<attacks;
	}
	return 0;
}

Learning course: STLs in C++
Problem Link: Save Konoha Practice Problem in STLs in C++ - CodeChef