#include<stdio.h> #include<math.h> double x[100],y[100]; int main() { int n; int time=0; while(scanf("%d",&n)!=EOF,n!=0) { int j; int m; double s=0; for(j=0;j<=n;j++) { scanf("%d",&m); if(m==0) break; int i; for(i=1;i<=m;i++) scanf("%lf%lf",&x[i],&y[i]); double sum=0; for(i=2;i<m;i++) { sum=sum+fabs((x[i]-x[1])*(y[i+1]-y[1]))+fabs((x[i+1]-x[1])*(y[i]-y[1])); } s+=sum; } printf("Case #%d: ",++time); printf("%.4f\n",s/2); } return 0; } |
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