poj 2528 Mayor's posters 线段树

/******************************************************
* File Name:   2528.cpp
* Author:      kojimai
* Creater Time:2014年08月26日 星期二 18时18分11秒
******************************************************/

#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
#include<iostream>
using namespace std;
#define FFF 10005
struct nodes
{
int x,y;
}p[FFF];

struct seg
{
int l,r,c;
}node[FFF*10];

struct order
{
int x,num;
}s[FFF*2];
bool cmp(order a,order b)
{
return a.x<b.x;
}

void buildtree(int l,int r,int num)
{
node[num].l=l;
node[num].r=r;
node[num].c=0;
if(l==r)
return;
int mid=(l+r)/2;
buildtree(l,mid,num*2);
buildtree(mid+1,r,num*2+1);
}

void solve(int l,int r,int num,int c)
{
//cout<<"nodel="<<node[num].l<<" noder="<<node[num].r<<endl;
if(node[num].l==l&&node[num].r==r)
{
node[num].c=c;
//cout<<" l="<<l<<" r="<<r<<" c="<<node[num].c<<endl;
return;
}
if(node[num].c>0&&node[num].r>node[num].l)
{
node[num*2].c=node[num].c;
node[num*2+1].c=node[num].c;
node[num].c=0;
}
//cout<<" l="<<l<<" r="<<r<<" c="<<node[num].c<<endl;
if(node[num].l==node[num].r)
return;
int mid=(node[num].l+node[num].r)/2;
if(mid>r)
{
solve(l,r,num*2,c);
}
else if(mid<l)
{
solve(l,r,num*2+1,c);
}
else
{
solve(l,mid,num*2,c);
solve(mid+1,r,num*2+1,c);
}
return;
}

int ans;
bool vis[FFF];
void search(int num)
{
if(node[num].c)
{
if(!vis[node[num].c])
{
ans++;
vis[node[num].c]=true;
}
return;
}
else
{
if(node[num].r>node[num].l)
{
search(num*2);
search(num*2+1);
}
}
return;
}

int main()
{
int keng;
scanf("%d",&keng);
while(keng--)
{
int n;
scanf("%d",&n);
for(int i=0;i<n;i++)
{
scanf("%d%d",&p[i].x,&p[i].y);
s[i*2].x=p[i].x;
s[i*2].num=-i-1;
s[i*2+1].x=p[i].y;
s[i*2+1].num=i+1;
}
sort(s,s+n*2,cmp);
int cnt=0,tmp=-1;
for(int i=0;i<n*2;i++)
{
if(tmp!=s[i].x)
{
tmp=s[i].x;
cnt++;
}
if(s[i].num<0)
p[-s[i].num-1].x=cnt;
else
p[s[i].num-1].y=cnt;
}
buildtree(1,cnt,1);
for(int i=0;i<n;i++)
{
solve(p[i].x,p[i].y,1,i+1);
}
ans=0;
search(1);
memset(vis,false,sizeof(vis));
cout<<ans<<endl;
}
return 0;
}