34 lines
890 B
C++
34 lines
890 B
C++
#include <stdio.h>
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struct point{
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int x,y;
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}p[3],m[3];
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int gcd(int a,int b){
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int c;
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while(b){
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c=a%b;
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a=b;
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b=c;
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}
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return a;
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}
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int abs(int x){
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return x>0?x:-x;
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}
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int S(point p1,point p2,point p0){
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return abs((p1.x-p0.x)*(p2.y-p0.y)-(p1.y-p0.y)*(p2.x-p0.x));
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}
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int main(){
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int sum,s,ans;
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while(~scanf("%d%d%d%d%d%d",&p[0].x,&p[0].y,&p[1].x,&p[1].y,&p[2].x,&p[2].y)){
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if(!p[0].x&&!p[0].y&&!p[1].x&&!p[1].y&&!p[2].x&&!p[2].y)break;
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m[0].x=abs(p[0].x-p[1].x);m[0].y=abs(p[0].y-p[1].y);
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m[1].x=abs(p[1].x-p[2].x);m[1].y=abs(p[1].y-p[2].y);
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m[2].x=abs(p[0].x-p[2].x);m[2].y=abs(p[0].y-p[2].y);
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sum=gcd(m[0].x,m[0].y)+gcd(m[1].x,m[1].y)+gcd(m[2].x,m[2].y);
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s=S(p[1],p[2],p[0]);
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ans=(s-sum+2)/2;
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printf("%d\n",ans);
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}
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return 0;
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}
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