职务地址：POJ 2954

意甲冠军：三个顶点的三角形，给出，内部需求格点数。

思考：就像POJ 1265。

#include <stdio.h>

#include <math.h>

#include <string.h>

#include <stdlib.h>

#include <iostream>

#include <sstream>

#include <algorithm>

#include <set>

#include <queue>

#include <stack>

#include <map>

using namespace std;

typedef long long LL;

const int inf=0x3f3f3f3f;

const double pi= acos(-1.0);

const double esp=1e-6;

int gcd(int a,int b)

{

    while(b){

        int r=b;

        b=a%b;

        a=r;

    }

    return a;

}

int main()

{

    int x1,y1,x2,y2,x3,y3;

    double S;

    int in,on;

    while(~scanf("%d %d %d %d %d %d",&x1,&y1,&x2,&y2,&x3,&y3)){

        in=on=S=0;

        if(!x1&&!y1&&!x2&&!y2&&!x3&&!y3) break;

        S=(x2-x1)*(y3-y1)-(x3-x1)*(y2-y1);

        if(S<0)

            S=-S;

        on=gcd(abs(x2-x1),abs(y2-y1))+gcd(abs(x1-x3),abs(y1-y3))+gcd(abs(x3-x2),abs(y3-y2));

        in=(S+2-on)/2;

        printf("%d\n",in);

    }

    return 0;

}