Submission #395437

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Source Code Expand

#include<iostream>
#include<cmath>
#include<cstdio>
using namespace std;
typedef struct point{
  double x, y;
}point;

double func(point a){
  return sqrt(a.x*a.x + a.y*a.y);
}

int main(int argc, char *argv[]){
  point a, b, c;
  cin >> a.x >> a.y >>
    b.x >> b.y >>
    c.x >> c.y;
  b.x -= a.x;b.y -= a.y;
  c.x -= a.x;c.y -= a.y;
  double theta = atan2(b.y, b.x) - atan2(c.y, c.x);
  if(theta > M_PI)theta -= M_PI;
  printf("%lf\n", func(b)*func(c)*sin(theta)/2);
  return 0;
}

Submission Info

Judge Result