poj 1151 (未完成) 扫描线 线段树 离散化

#include<iostream>
#include<vector>
#include<cmath>
#include<algorithm>
using namespace std;
#define y1 y11
#define ls rt<<1,l,m
#define rs rt<<1|1,m+1,r
const int maxn=1e3+10;
double x1[maxn];
double y1[maxn];
double x2[maxn];
double y2[maxn];
vector<double> vx;
vector<double> vy;
double x[maxn];
double y[maxn];
struct node { int yl,yr,k; }pp[maxn];
vector<node> vxxx[maxn];
double tree[4*maxn];
double  ans[4*maxn];
int    lazy[4*maxn];

int tot=0;
void push_up(int rt) {  tree[rt]=tree[rt<<1]+tree[rt<<1|1]; }
//void push_down(int rt,int len) {  lazy[rt<<1]+=lazy[rt];  lazy[rt<<1|1]+=lazy[rt];  lazy[rt]=0; }
void build(int rt,int l,int r)
{
    if(l==r) {  tot++; tree[l]=vy[tot]-vy[tot-1]; return ; }
    int m=(l+r)>>1;   build(ls);  build(rs);push_up(rt);
}
void update(int p,int delta,int rt,int l,int r)
{
    if(l==r) { tree[rt]+=delta; return ; }
    int m=(l+r)>>1;
    if(p<=m)update(p,delta,ls);
    else update(p,delta,rs);
    push_up(rt);
}
void Update(int L,int R,int delta,int rt,int l,int r)
{
    if(L<=l&&r<=R) {  lazy[rt]+=delta; return ; }
    if(lazy[rt])  push_down(rt,r-l+1);
    int m=(l+r)>>1;
    if(L<=m)Update(L,R,delta,ls);
    if(R>m)Update(L,R,delta,rs);
    push_up(rt);
}
int main()
{
    int cnt=0;
    int n;
    while(1)
    {
        scanf("%d",&n);        if(n==0) break;
        for(int i=1;i<=n;i++)  scanf("%lf %lf %lf %lf",&x1[i],&y1[i],&x2[i],&y2[i]);
        for(int i=1;i<=n;i++)
        {
            vx.push_back(x1[i]);
            vx.push_back(x2[i]);
            vy.push_back(y1[i]);
            vy.push_back(y2[i]);
        }
        sort(vx.begin(),vx.end());  vx.erase(unique(vx.begin(),vx.end()),vx.end());
        for(int i=0;i<vx.size();i++) x[i]=vx[i];
        sort(vy.begin(),vy.end());  vy.erase(unique(vy.begin(),vy.end()),vy.end());
        for(int i=0;i<vy.size();i++) y[i]=vy[i];
        for(int i=1;i<=n;i++)
        {
            int k=lower_bound(vx.begin(),vx.end(),x1[i])-vx.begin();
            node p;    p.yl=y1[i]; p.yr=y2[i]; p.k=1;
            vxxx[k].push_back(p);
            k=lower_bound(vx.begin(),vx.end(),x2[i])-vx.begin();
            p.k=-1;
            vxxx[k].push_back(p);
        }
        int m=vy.size()-1;
        build(1,1,m);
        double ans=0;
        for(int i=0;i<vx.size();i++)
        {
               if(i==0)
               {
                   for(int j=0;j<=vxx[i].size();j++)
                   {
                       node p=vxxx[i][j];
                       int l=lower_bound(vy.begin(),vy.end(),p.yl)-vy.begin();
                       int r=lower_bound(vy.begin(),vy.end(),p.yr)-vy.begin();
                       update(l,r,p.k,1,1,m);
                   }
               }
        }
    }
}

标签：rt,int,double,1151,tree,poj,扫描线,maxn,include
来源： https://www.cnblogs.com/Andromeda-Galaxy/p/10574798.html