OJ-Problems-Source/HDOJ/2907_autoAC.cpp
2016-08-24 18:27:13 +08:00

67 lines
1.4 KiB
C++

#include<stdio.h>
#include<string.h>
#include<algorithm>
using namespace std;
struct aa
{
int x,y;
int t;
}a1[105],a2[105];
bool camp(aa a,aa b)
{
return a.y<b.y||a.y==b.y&&a.x<b.x;
}
bool fx(aa A,aa B,aa C)
{
return (B.x-A.x)*(C.y-A.y)>(B.y-A.y)*(C.x-A.x);
}
int main ()
{
int i,t,mt,n,s,tt,p,q;
bool mark[105][105];
scanf("%d",&tt);
while(tt--)
{
scanf("%d%d%d",&p,&q,&n);
memset(mark,0,sizeof(mark));
for(i=1;i<n;i++)
{
mark[i][i+1]=1;
mark[i+1][i]=1;
}
mark[1][n]=mark[n][1]=1;
for(i=1;i<=n;i++)
{
scanf("%d%d",&a1[i].x,&a1[i].y);
a1[i].t=i;
}
sort(a1+1,a1+n+1,camp);
a2[1]=a1[1];
for(t=1,i=2;i<=n;i++)
{
while(t!=1&&!fx(a2[t-1],a2[t],a1[i]))
t--;
a2[++t]=a1[i];
}
mt=t;
a2[++t]=a1[n-1];
for(i=n-2;i>=1;i--)
{
while(t!=mt&&!fx(a2[t-1],a2[t],a1[i]))
t--;
a2[++t]=a1[i];
}
for(s=0,t--,i=1;i<t;i++)
if(!mark[a2[i].t][a2[i+1].t])
s++;
if(!mark[a2[1].t][a2[t].t])
s++;
int ans=-p*s+q*(t-s);
if(ans>0)
printf("%d\n",ans);
else
printf("0\n");
}
return 0;
}