RT，怎么写？

#include <bits/stdc++.h>
using namespace std;
int n,a,b;
int w[500005];
bool check(int x)
{
	long long minecraft=x*(a*n+b);
	for(int i=1; i<=n; i++)
	{
		minecraft-=w[i];
	}
	return minecraft>=0;
}
int main() 
{
	cin>>n>>a>>b;
	for(int i=1; i<=n; i++) cin>>w[i];
	int l=1,r=500000,ans=-1;
	while(l<=r)
	{
		int mid=l+(r-l)/2;
		if(check(mid))
		{
			r=mid-1;
			ans=mid;
		}
		else
		{
			l=mid+1;
		}
	}
	cout<<ans;
	return 0;
}