poj 1113 凸包 虽然A了 但补来补去，代码已经惨不忍睹了

题目描述：http://poj.org/problem?id=1321

典型的凸包 ，求凸包周长再加上一个圆的周长

注意：输出时别用%.lf  原因：http://bbs.byr.cn/#!article/ACM_ICPC/45379

32ms 

如果你想研究者道题的话还是绕道吧，看一下那些大牛的代码把

#include <stdio.h>
#include <stdlib.h>
#include<math.h>
struct a
{
    int x;
    int y;
    double an;
};
int si=-1;
void push(struct a a[],struct a s)
{
    si+=1;
    a[si]=s;
}
struct a pop(struct a a[])
{
    si-=1;
    return a[si+1];
}
struct a top1(struct a a[])
{
    return a[si];
}
struct a top2(struct a a[])
{
    return a[si-1];
}

int one(struct a a[],int p,int r)
{
    int i,j;
    struct a temp,x;
    x=a[r];
    i=p-1;
    for(j=p;j<=r-1;j++)
    {
        if(a[j].an<=x.an)
        {
            i+=1;
            temp=a[i];
            a[i]=a[j];
            a[j]=temp;
        }

    }
    temp=a[i+1];
    a[i+1]=a[r];
    a[r]=temp;
    return i+1;
}
void quicksort(struct a a[],int p,int r )
{
    int q;
    if(p<r)
    {
        q=one(a,p,r);
        quicksort(a,p,q-1);
        quicksort(a,q+1,r);
    }
}

int main(int argc, char** argv) {

    int n,i,i1,k,z,temi,yx=100000,j,j1;
    double maxx=-100000,maxy=-100000,sum;
    struct a zb[1050],zb1[1050],temp,to1,to2,tm;
    scanf("%d %d",&n,&z);
    for(i=0;i<n;i++)
    {
        scanf("%d %d",&zb[i].x,&zb[i].y);

        if(maxy<zb[i].y)
        {
            maxy=zb[i].y;
            maxx=zb[i].x;
            temi=i;
        }
        else if(maxy==zb[i].y)
        {
        if(zb[i].x>maxx)
        {
            maxx=zb[i].x;
            temi=i;
        }
        }
    }
    //angle
    temp=zb[n-1];
    zb[n-1]=zb[temi];
    zb[temi]=temp;
    --n;

    for(i=0;i<n;i++)
    {
        if((zb[i].x-zb[n].x)!=0)
        {
        zb[i].an=(zb[i].y-zb[n].y)*1.0/(zb[i].x-zb[n].x);
        }
        else
        {
            zb[i].an=100000;
        }
    }
    quicksort(zb,0,n-1);
    zb1[0]=zb[0];
    k=0;
    for(i=1;i<n;i++)
    {
        if(zb[i].an==zb1[k].an)
        {
            
            if((zb[i].x-zb[n].x)*(zb[i].x-zb[n].x)+(zb[i].y-zb[n].y)*(zb[i].y-zb[n].y)>(zb1[k].x-zb[n].x)*(zb1[k].x-zb[n].x)+(zb1[k].y-zb[n].y)*(zb1[k].y-zb[n].y))
            {
                zb1[k]=zb[i];
            }
           
        }
         else
            {
                k++;
                zb1[k]=zb[i];
            }
    }
    if(k>=1)
    {
    //judge
    for(i=0;i<=k;i++)
    if(zb1[i].an>=0.0)
    break;
    if(i==k+1)
    {
        i=0;
    }
    tm=zb[n];
    push(zb,tm);
    push(zb,zb1[i]);
   for(j=i+1;j<=k+i;j++)
    {
        to1=top1(zb);
        to2=top2(zb);
    j1=j%(k+1);
        while((zb1[j1].x-to1.x)*(to1.y-to2.y)-(to1.x-to2.x)*(zb1[j1].y-to1.y)>0)
        {
            pop(zb);
            to1=top1(zb);
            to2=top2(zb);
        }
        push(zb,zb1[j1]);
    }
    sum=0;
    for(i=0;i<si;i++)
    {

        sum+=sqrt((zb[i].x-zb[i+1].x)*(zb[i].x-zb[i+1].x)+(zb[i].y-zb[i+1].y)*(zb[i].y-zb[i+1].y));
    }

    sum+=sqrt((zb[si].x-zb[0].x)*(zb[si].x-zb[0].x)+(zb[si].y-zb[0].y)*(zb[si].y-zb[0].y));
    //sum+=sqrt((zb[0].x-tm.x)*(zb[0].x-tm.x)+(zb[0].y-tm.y)*(zb[0].y-tm.y));
    printf("%.f\n",(sum+3.141592653*z*2));
}
else
{
    
    printf("%.f\n",(2*sqrt((zb[n].x-zb1[k].x)*(zb[n].x-zb1[k].x)+(zb[n].y-zb1[k].y)*(zb[n].y-zb1[k].y))+3.141592653*2*z));

}
    return (EXIT_SUCCESS);
}