HDU5979水题

水题
code：

#include<cstdio>#include<cmath>#include<iostream>using namespace std;const double PI=acos(-1.00);int main(){    int n,d;    while(scanf("%d%d",&n,&d)!=EOF)    {        double sum=0;        double tmp;        for(int i=0;i<n;i++)        {            scanf("%lf",&tmp);            sum+=(0.50*sin(tmp/180.000*PI)*(double)d*(double)d);        }        printf("%.3f\n",sum);    }}