hdu 4946 Area of Mushroom

#include<stdio.h>
#include<algorithm>
#include<fstream>
#include<string.h>
#include<iostream>
using namespace std;
const int MAX=550;
struct point
{
    int x;
    int y;
    int v;
    int i;
}p[MAX],Ini[MAX],res[MAX];
int ans[MAX];
bool cmp(point A,point B)
{
    if(A.y==B.y)return A.x<B.x;
    return A.y<B.y;
}
bool cmp1(point A,point B)
{
    if(A.v>B.v)return true;
    if(A.v==B.v)
    {
        if(A.x<B.x)return true;
        if(A.x==B.x&&A.y<B.y)return true;
    }
    return false;
}
int cross(point A,point B,point C)
{
    return (B.x-A.x)*(C.y-A.y)-(C.x-A.x)*(B.y-A.y);
}
int Graham(point *p,int n)
{
    //if (n<3)return n;
    sort(p,p+n,cmp);
    int i;
    int top=0;
    for(i=0;i<n;i++)
    {
        while(top>=2&&cross(res[top-2],res[top-1],p[i])<0)
            top--;
        res[top++]=p[i];
    }
    int t=top+1;
    for(i=n-2;i>=0;i--)
    {
        while(top>=t&&cross(res[top-2],res[top-1],p[i])<0)
            top--;
        res[top++]=p[i];
    }
    /*for(i=0;i<top;i++)
        printf("%d %d\n",res[i].x,res[i].y);*/
    return top;
}
int main()
{
    int n;
    int i,j;
    //ifstream cin("A.txt");
    int __case=0;
    while(cin>>n&&n)
    {
        for(i=0;i<n;i++)
        {
            cin>>Ini[i].x>>Ini[i].y>>Ini[i].v;
            Ini[i].i=i;
        }
        sort(Ini,Ini+n,cmp1);
            //cout<<Ini[i-1].x<<Ini[i-1].y;
        int tmp=0;
        for(i=0;i<n;i++)
        {
            if(Ini[0].v==Ini[i].v)tmp++;
            else break;
        }
        point po;
        for(i=0,j=0;i<tmp;)
        {
            po=Ini[i];
            if(i<tmp-1&&Ini[i+1].x==Ini[i].x&&Ini[i+1].y==Ini[i].y)
            {
                while(i<tmp-1&&Ini[i+1].x==Ini[i].x&&Ini[i+1].y==Ini[i].y)
                    i++;
            }
            else
            {
                p[j++]=po;
            }
            i++;
        }
        printf("Case #%d: ",++__case);

        int m=Graham(p,j);

        memset(ans,0,sizeof(ans));
        for(i=0;i<m;i++)
        {
            //printf("%d %d %d",res[i].x,res[i].y,res[i].v);
            if(res[i].v>0)
            {
                ans[res[i].i]=1;
            }
        }
        for(i=0;i<n;i++)
            printf("%d",ans[i]);
        printf("\n");
    }
    return 0;
}