【HDU】3265 Posters

#include<cstdio>
#include<cstring>
#include<cstdlib>
#define MAXN 50010
typedef __int64 LL;
struct Line
{
    int left,right,high,flag;
};
struct node
{
    int cover,len;
};
Line p[MAXN<<3];
node tree[MAXN<<5];
int cnt,x[MAXN<<3];
inline void Post(int x1,int y1,int x2,int y2)
{
    if(x1!=x2&&y1!=y2)
    {
        x[cnt]=x1;
        p[cnt].left=x1;
        p[cnt].right=x2;
        p[cnt].high=y1;
        p[cnt++].flag=1;
        x[cnt]=x2;
        p[cnt].left=x1;
        p[cnt].right=x2;
        p[cnt].high=y2;
        p[cnt++].flag=-1;
    }
}
int cmp1(const void *a,const void *b)
{
    return *(int *)a-*(int *)b;
}
int cmp2(const void *a,const void *b)
{
    return (*(Line *)a).high-(*(Line *)b).high;
}
int Bin(int val,int low,int high)
{
    int mid;
    while(low<high)
    {
        mid=(low+high)>>1;
        if(x[mid]==val)
            return mid;
        if(x[mid]<val)
            low=mid+1;
        else
            high=mid;
    }
}
void Build(int L,int R,int rt)
{
    tree[rt].len=tree[rt].cover=0;
    if(L!=R)
    {
        int mid=(L+R)>>1;
        Build(L,mid,rt<<1);
        Build(mid+1,R,rt<<1|1);
    }
}
inline void PushUp(int L,int R,int rt)
{
    if(tree[rt].cover)
        tree[rt].len=x[R+1]-x[L];
    else if(L==R)
        tree[rt].len=0;
    else
        tree[rt].len=tree[rt<<1].len+tree[rt<<1|1].len;
}
void Update(int st,int en,int flag,int L,int R,int rt)
{
    if(st<=L&&R<=en)
    {
        tree[rt].cover+=flag;
        PushUp(L,R,rt);
    }
    else
    {
        int mid=(L+R)>>1;
        if(mid>=st)
            Update(st,en,flag,L,mid,rt<<1);
        if(en>mid)
            Update(st,en,flag,mid+1,R,rt<<1|1);
        PushUp(L,R,rt);
    }
}
int main()
{
    LL ans;
    int i,n,m,st,en,x1,y1,x2,y2,x3,y3,x4,y4;
    while(scanf("%d",&n),n)
    {
        for(cnt=i=0;i<n;i++)
        {
            scanf("%d%d%d%d%d%d%d%d",&x1,&y1,&x2,&y2,&x3,&y3,&x4,&y4);
            Post(x1,y1,x2,y3);
            Post(x1,y4,x2,y2);
            Post(x1,y3,x3,y4);
            Post(x4,y3,x2,y4);
        }
        qsort(x,cnt,sizeof(x[0]),cmp1);
        qsort(p,cnt,sizeof(p[0]),cmp2);
        for(i=m=0;i<cnt;i++)
        {
            if(x[i]!=x[m])
                x[++m]=x[i];
        }
        Build(0,m,1);
        for(ans=i=0;i<cnt-1;i++)
        {
            st=Bin(p[i].left,0,m+1);
            en=Bin(p[i].right,0,m+1);
            Update(st,en-1,p[i].flag,0,m,1);
            ans+=(LL)(p[i+1].high-p[i].high)*tree[1].len;
        }
        printf("%I64d\n",ans);
    }
    return 0;
}