#include<iostream> #include<cmath> #include<stdio.h> #include<algorithm> using namespace std; typedef struct{ int x,y; }Coor; Coor a[5000]; double area; double Area(int p1, int p2, int p3){ return 0.5*fabs((a[p2].x -a[p1].x )*(a[p3].y - a[p2].y ) - (a[p3].x...