AC x13
TLE x15

#include<iostream>
using namespace std;
int n,a[200005],l=1,r=-1,ans;
long long m,suma;
bool check(int x){
	long long sum=0;
	for(int i=1;i<=n;i++) sum+=min(x,a[i]);
	return sum<=m;
}
int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	cin>>n>>m;
	for(int i=1;i<=n;i++){
		cin>>a[i];
		r=max(r,a[i]);
		suma+=a[i];
	}
	if(suma<=m){
		cout<<"infinite"<<endl;
		return 0;
	}
	while(l<r){
		int mid=(l+r)/2;
		if(check(mid)){
			l=mid;
			ans=mid;
		}else r=mid-1;
	}
	cout<<ans<<endl;
	return 0;
}

思路：二分答案。