PKU2954

这道题目主要用到PICK定理，即，整点多边形的面积=内部整点个数+边上的整点个数/2 - 1.

至于边上的点个数，用到GCD函数求。...貌似还有个类似的题目...

#include <iostream>#include <string.h>#include <math.h>#include <stdio.h>using namespace std;struct node{int x,y;}a,b,c;int gcd(int a,int b){if(b==0) return a;else return gcd(b,a%b); }int main(){int l,num;while(scanf("%d %d %d %d %d %d",&a.x,&a.y,&b.x,&b.y,&c.x,&c.y)!=EOF&& (a.x||a.y||b.x||b.y||c.x||c.y)){l=gcd(abs(a.x-b.x),abs(a.y-b.y))+gcd(abs(a.x-c.x),abs(a.y-c.y))+gcd(abs(c.x-b.x),abs(c.y-b.y));int s=abs((b.x-a.x)*(c.y-a.y)-(c.x-a.x)*(b.y-a.y))/2;num=s+1-l/2;printf("%d/n",num);}return 0;}