POJ 1151 离散化线段树＋计算几何正矩形求并

我觉得像我这样把所有东西都写的类的ACMer真是一个异类。。。

 

//Result:wizmann    1151    Accepted    832K    0MS    G++    3310B    
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <string>
#include <cmath>
#include <vector>
#include <set>
#include <map>
#include <iostream>

using namespace std;

#define print(x) cout<<x<<endl
#define input(x) cin>>x
#define SIZE 128

struct node
{
    int st,end;
    double len;
    int cov;

    node(){}
    node(int ist,int iend,double ilen)
    {
        cov=0;
        st=ist;end=iend;
        len=ilen;
    }
    
    bool equal(int a,int b)
    {
        return st==a && end==b;
    }
    
    int getmid()
    {
        return (st+end)>>1;
    }
    
    bool endnode()
    {
        return end-st<=1;
    }
};

struct point
{
    double x,y;
    point(){}
    point(double i_x,double i_y)
    {
        x=i_x;y=i_y;
    }
};

struct segment
{
    point p1,p2;

    segment(){}
    segment(const point& a,const point& b)
    {
        p1=a;p2=b;
    }
};

struct line
{
    double y;
    int x1,x2;
    int flag;
    line(){}
    line(int ix1,int ix2,double iy,int iflag)
    {
        x1=ix1;x2=ix2;
        y=iy;flag=iflag;
    }
    friend bool operator < (const line& a,const line& b)
    {
        return a.y<b.y;
    }
};

const int ROOT=0;


node stree[SIZE<<2];
int n;
map<double,int> hash;
map<int,double> anti_hash;
int sz,ind;
line edge[SIZE<<1];


inline int left(int x)
{
    return (x<<1)+1;
}
inline int right(int x)
{
    return left(x)+1;
}

void stree_init(int l,int r,int pos=ROOT)
{
    stree[pos]=node(l,r,anti_hash[r+1]-anti_hash[l]);
    if(l<r)
    {
        int mid=(l+r)>>1;
        stree_init(l,mid,left(pos));
        stree_init(mid+1,r,right(pos));
    }
}

void update(int l,int r,int cov,int pos=ROOT)
{
    if(stree[pos].equal(l,r))
    {
        stree[pos].cov+=cov;
    }
    else
    {
        int mid=stree[pos].getmid();
        if(r<=mid) update(l,r,cov,left(pos));
        else if(l>mid) update(l,r,cov,right(pos));
        else
        {
            update(l,mid,cov,left(pos));
            update(mid+1,r,cov,right(pos));
        }
    }
}

double query(int pos=ROOT)
{
    double res=0;
    if(stree[pos].cov>0) res+=stree[pos].len;
    else if(stree[pos].st!=stree[pos].end)
    {
        res+=query(left(pos));
        res+=query(right(pos));
    }
    return res;
}

int main()
{
    double bx,by,ex,ey;
    int cas=1;
    while(input(n) && n)
    {
        hash.clear();
        anti_hash.clear();
        vector<double> itemx;
        vector<segment> seg;
        for(int i=0;i<n;i++)
        {
            scanf("%lf%lf%lf%lf",&bx,&by,&ex,&ey);
            itemx.push_back(bx);
            itemx.push_back(ex);
            seg.push_back(segment(point(bx,by),point(ex,by)));
            seg.push_back(segment(point(bx,ey),point(ex,ey)));
        }
        sort(itemx.begin(),itemx.end());
        sz=itemx.size();
        ind=0;
        double ans=0;
        for(int i=0;i<sz;i++)
        {
            if(hash.find(itemx[i])==hash.end())
            {
                //print(itemx[i]<<' '<<ind);
                hash[itemx[i]]=ind;
                anti_hash[ind]=itemx[i];
                ind++;
            }
        }
        sz=seg.size();
        for(int i=0;i<(int)seg.size();i+=2)
        {
            edge[i]=line(hash[seg[i].p1.x],hash[seg[i].p2.x]-1,seg[i].p1.y,1);
            edge[i+1]=line(hash[seg[i+1].p1.x],hash[seg[i+1].p2.x]-1,seg[i+1].p1.y,-1);
        }
        sort(edge,edge+sz);
        stree_init(0,ind-1);
        update(edge[0].x1,edge[0].x2,edge[0].flag);
        for(int i=1;i<sz;i++)
        {
            ans+=fabs(edge[i-1].y-edge[i].y)*query();
            update(edge[i].x1,edge[i].x2,edge[i].flag);
        }
        printf("Test case #%d\n",cas++);
        printf("Total explored area: %.2f\n\n",ans); 
    }
    return 0;
}