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OI-source/history_source/信息学奥赛一本通/1.2.6.10.cpp
2023-08-03 09:22:52 +08:00

18 lines
270 B
C++

#include<cstdio>
#include<cmath>
using namespace std;
int main()
{
double a,b,c;
scanf("%lf%lf%lf",&a,&b,&c);
if(!(a+b>c&&a+c>b&&b+c>a)) printf("no\n");
else
{
double p=(a+b+c)/2.0;
double ans=sqrt(p*(p-a)*(p-b)*(p-c));
printf("%lf\n",ans);
}
return 0;
}