hdu 1700 poj 2954

#include<cstdio>
#include<cstring>
#include<iostream>
using namespace std;
struct point
{
int x,y;
};
int gcd(int a,int b)
{
return b==0?a:gcd(b,a%b);
}
int main()
{
point a,b,c;
int i,j;
while(1)
{
int area,e,i;
scanf("%d%d%d%d%d%d",&a.x,&a.y,&b.x,&b.y,&c.x,&c.y);
if(!a.x && !a.y && !b.x && !b.y && !c.x && !c.y) break;
area=(b.x-a.x)*(c.y-a.y)-(c.x-a.x)*(b.y-a.y);
area=area>0?area:-area;
e=gcd(abs(b.x-a.x),abs(b.y-a.y))+gcd(abs(c.x-b.x),abs(c.y-b.y))+gcd(abs(a.x-c.x),abs(a.y-c.y));
i=(area-e+2)/2;
printf("%d/n",i);
}
return 0;
}