nyoj-6

　贪心:

　注意：半径小于1的肯定不行。

#include<iostream>#include<cmath>#include<algorithm>using namespace std;#define N 1024double a[N];bool cmp(double a,double b){return a>b;}int main(){int n,m,i;double sum;cin>>m;while(m--){cin>>n;for(i=0;i<n;++i)cin>>a[i];sum=0;sort(a,a+n,cmp);for(i=0;sum<20;++i)sum+=sqrt(a[i]*a[i]-1)*2;cout<<i<<endl;}return 0;}