题解

#include<iostream>
#include<cmath>
#include<algorithm>
#include<cstring>
using namespace std;
float Tri(float radius , float width){
	return 2*sqrt(radius*radius - width*width);
}
bool cmp(float a,float b){
	return a>b;
}
int main(){
	int m,n;
	float a[601], sum,temp;
	cin>>m;
	while (m--){
		sum = 0.0;
		cin>>n;
		for (int i = 0; i < n; i++){
			scanf("%f", &a[i]);
		}
 
 		sort(a,a+n,cmp);
		for (int i = 0; i < n; i++){
			sum += (Tri(a[i],1.0));
			if (sum >= 20){
				cout<<i+1<<endl;
				break;
			}
		}
	}
	return 0;
}