hdu 3265 矩形剪块面积并

http://acm.hust.edu.cn/vjudge/problem/10769

给n张海报，在每张海报上剪掉一个矩形，求面积并

把剪块的海报分成四个矩形，就是普通的求面积并问题了

#include <iostream>
#include <string>
#include <cstring>
#include <cstdlib>
#include <cstdio>
#include <cmath>
#include <algorithm>
#include <stack>
#include <queue>
#include <cctype>
#include <vector>
#include <iterator>
#include <set>
#include <map>
#include <sstream>
using namespace std;

#define mem(a,b) memset(a,b,sizeof(a))
#define pf printf
#define sf scanf
#define spf sprintf
#define pb push_back
#define debug printf("!
")
#define MAXN 50000+5
#define MAX(a,b) a>b?a:b
#define blank pf("
")
#define LL long long
#define ALL(x) x.begin(),x.end()
#define INS(x) inserter(x,x.begin())
#define pqueue priority_queue
#define INF 0x3f3f3f3f

#define ls (rt<<1)
#define rs (rt<<1|1)

int n,m;

int hh[MAXN],col[MAXN<<3],len[MAXN<<3];

struct node
{
    int l,r,x,c;
    node(){}
    node(int a,int b,int c,int d):l(a),r(b),x(c),c(d){}
    bool operator < (const node &b) const
    {
        return x<b.x;
    }
}a[MAXN<<3];

void PushUp(int rt,int l,int r)
{
    if(col[rt])
    {
        len[rt] = hh[r+1] - hh[l];
    }
    else if(l==r) len[rt] = 0;
    else
    {
        len[rt] = len[ls]+len[rs];
    }
}

void update(int val,int L,int R,int l,int r,int rt)
{
    if(L<=l && r<=R)
    {
        col[rt] += val;
        PushUp(rt,l,r);
        return;
    }
    int mid = (l+r)>>1;
    if(L <= mid) update(val,L,R,l,mid,ls);
    if(R > mid) update(val,L,R,mid+1,r,rs);
    PushUp(rt,l,r);
}

int main()
{
    int i,j,k,t,kase=1;
    while(~sf("%d",&n) && n)
    {
        int v=0;
        LL sum = 0;
        for(i=0;i<n;i++)
        {
            int x1,y1,x2,y2;
            int X1,Y1,X2,Y2;
            sf("%d%d%d%d%d%d%d%d",&x1,&y1,&x2,&y2,&X1,&Y1,&X2,&Y2);
            if(x1!=X1)
            {
                hh[v] = y1;
                a[v++] = node(y1,y2,x1,1);
                hh[v] = y2;
                a[v++] = node(y1,y2,X1,-1);
            }
            if(x2!=X2)
            {
                hh[v] = y1;
                a[v++] = node(y1,y2,X2,1);
                hh[v] = y2;
                a[v++] = node(y1,y2,x2,-1);
            }
            if(y1!=Y1)
            {
                hh[v] = y1;
                a[v++] = node(y1,Y1,X1,1);
                hh[v] = Y1;
                a[v++] = node(y1,Y1,X2,-1);
            }
            if(y2!=Y2)
            {
                hh[v] = Y2;
                a[v++] = node(Y2,y2,X1,1);
                hh[v] = y2;
                a[v++] = node(Y2,y2,X2,-1);
            }
        }
        sort(hh,hh+v);
        sort(a,a+v);
        int d = 1;
        for(i=1;i<v;i++)
        {
            if(hh[i]!=hh[i-1]) hh[d++] = hh[i];
        }
        mem(len,0);
        mem(col,0);
        for(i=0;i<v-1;i++)
        {
            int l = lower_bound(hh,hh+d,a[i].l)-hh;
            int r = lower_bound(hh,hh+d,a[i].r)-hh-1;
            update(a[i].c,l,r,0,d-1,1);
            sum+=len[1]*((long long)a[i+1].x-a[i].x);
            //pf("%lf %lf
",sum,len[1]);
        }
        pf("%I64d
",sum);
    }

    return 0;
}