HDU 4386 Quadrilateral 简略几何

HDU 4386 Quadrilateral 简单几何

#include <set>
#include <map>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <cctype>
#include <cstdio>
#include <string>
#include <vector>
#include <cassert>
#include <cstdlib>
#include <cstring>
#include <sstream>
#include <iostream>
#include <algorithm>
using namespace std;
int max(int a,int b){return a<b?b:a;}
int min(int a,int b){return a>b?b:a;}
int main()
{
	int cas,t=1;
	cin>>cas;
	while(cas--)
	{
		double a,b,c,d;
		{
			cin>>a>>b>>c>>d;
			bool f=1;
			double s=(a+b+c+d)/2;
			double ans=sqrt((s-a)*(s-b)*(s-c)*(s-d));
			if(a>=b+c+d || b>=a+c+d || c>=a+b+d || d>=a+b+c)
				printf("Case %d: -1\n",t++);
			else 
				printf("Case %d: %.6lf\n",t++,ans);

		}
	}
	return 0;
}

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具体就是海伦公式水过