1159E-农田开发

#include<iostream>using namespace std;int a[100][2];int main(){int n;cin>>n;int i;double area=0,sum=0;for(i=0;i<n;i++){cin>>a[i][0]>>a[i][1];}int j,k;for(i=0;i<n;i++){for(j=i+1;j<n;j++){for(k=j+1;k<n;k++){area=a[i][0]*a[j][1]+a[j][0]*a[k][1]+a[k][0]*a[i][1]-a[k][0]*a[j][1]-a[j][0]*a[i][1]-a[i][0]*a[k][1];area/=2;if(area<0)area=-area;if(sum<area)sum=area;}}}printf("%0.1f\n",sum);return 0;}