POJ - 2528 http://poj.org/problem?id=2528
以为过了但是看了discuss，有组数据有问题，先放着，之后会回来改。//在下面改正了。
想要学习骚气的写法所以改了改自己的线段树，第一次自己能主动想到离散化，结果还是有问题。

//离散化+线段树(区间更新)

/*过不了的数据
3
3
5 6
4 5
6 8
3    主要是这组
1 10
1 3
6 10
5
1 4
2 6
8 10
3 4
7 10
*/

#include <cstdio>
#include <iostream>
#include <cstring>
#include <map>
#include <set>
using namespace std;
#define met(a,b) memset(a,b,sizeof(a))
#define istr map<int, int> :: iterator
map<int,int> id;
map<int ,int > val;     //离散化
const int maxn = 1e5+10;

struct node{int l,r;}q[maxn];
set<int> re;

int d[maxn<<1],tag[maxn<<3];

int num = 0;int n;
void init()
{
    id.clear(); val.clear(); re.clear();
    num = 0;
    met(d,0);   met(tag,0);
}
void pre()
{
    for(int i = 1 ; i <= n ; i++)
    {
        int a,b;
        scanf("%d%d",&a,&b);
        id[a] = 1,id[b] = 1;
        q[i].l = a; q[i].r = b;
    }
    istr it = id.begin();
    for(; it != id.end(); it++)
        id[it->first] = ++num;
}

void pushup(int t,int id)
{
    tag[id<<1] = tag[id<<1|1] = t;
    tag[id] = 0;
}
void add(int al,int ar,int v,int l,int r,int id)
{
    if(r < al || l > ar )   return;
    if(r <= ar && l >= al){tag[id] = v;return ;}

    if(tag[id]) pushup(tag[id],id);
    int m = l+r>>1;
    if(al <= m) add(al,ar,v,l,m,id<<1);
    if(ar >  m) add(al,ar,v,m+1,r,id<<1|1);
}
void query(int ql,int qr,int id,int l,int r)
{
    //cout<<" l r" << l << " " << r<<endl;
    if(r < ql || l > qr) return;
    if(tag[id])
    {
        for(int i = l; i <= r; i++)
            d[i] = tag[id];
        return;
    }
    int m = l+r>>1;
    query(ql,qr,id<<1,l,m);
    query(ql,qr,id<<1|1,m+1,r);
}

int main()
{
    int t;
    scanf("%d",&t);
    while(t--)
    {
        init();
        scanf("%d",&n);
        pre();
        for(int i = 1; i <= n; i++)
            add(id[q[i].l],id[q[i].r],i,1,num,1);
        query(1,num,1,1,num);

        int ans = 0;
        //cout<<num<<endl;
        //for(int i = 1; i <= num; i++)
        //cout<<d[i]<<endl;


        for(int i = 1; i <= num; i++)
        {
            if(re.count(d[i]) == 0 && d[i] != 0)
            {
                ans++;
                re.insert(d[i]);
            }
        }
        printf("%d\n",ans);
    }
    return 0;
}

改了一下，主要是离散化的过程，因为poj是用的段的标号，把它改成点，再离散化，离散化后注意叶子值就不能是一个点了

#include <cstdio>
#include <iostream>
#include <cstring>
#include <map>
#include <set>
#include <algorithm>
using namespace std;
#define met(a,b) memset(a,b,sizeof(a))
#define istr map<int, int> :: iterator
map<int,int> id;

const int maxn = 2e5+10;
int x[maxn<<2];
struct node{int l,r;}q[maxn];
set<int> re;

int d[maxn << 2],tag[maxn << 3];

int xnum = 0;int n;
void init()
{
    id.clear();  re.clear();
    xnum = 0;
    met(d,0);    met(tag,0);
}

void pre()
{
    for(int i = 1 ; i <= n ; i++)
    {
        int a,b;
        scanf("%d%d",&a,&b);
        x[xnum++] = a; x[xnum++] = ++b;
        q[i].l = a; q[i].r = b;
    }
    sort(x,x + xnum);
    xnum = unique(x, x + xnum) - x;
    for(int i = 0; i < xnum; i++)
    {   id[ x[i] ] = i + 1; }
}

void pushup(int t,int id)
{
    tag[id<<1] = tag[id<<1|1] = t;
    tag[id] = 0;
}

void add(int al,int ar,int v,int l,int r,int id)
{
    //cout<<"id l r "<<id<<" "<< l << " " << r <<endl;
    if(r < al || l > ar )   return;
    if(r <= ar && l >= al){tag[id] = v;return ;}
    if(r == l+1){return;}
    if(tag[id]) pushup(tag[id],id);

    int m = l+r>>1;
    if(al < m) add(al,ar,v,l,m,id<<1);
    if(ar >=  m) add(al,ar,v,m,r,id<<1|1);
}

void query(int id,int l,int r)
{
    if(tag[id])
    {
        //cout<<id<<endl;
        for(int i = l; i < r; i++)
            d[i] = tag[id];
        tag[id] = 0;
        return;
    }

    if(r == l+1) return;
    int m = l+r>>1;

    query(id<<1,l,m);
    query(id<<1|1,m,r);
}

int main()
{
    //freopen("D:\\in.txt","r",stdin);
    int t;
    scanf("%d",&t);
    while(t--)
    {
        init();
        scanf("%d",&n);
        pre();
        for(int i = 1; i <= n; i++)
        {
           // int rid = q[i].l == q[i].r? id[q[i].r] : id[q[i].r] - 1;
            add(id[q[i].l],id[q[i].r],i,1,xnum,1);
        }

        query(1,1,xnum);
        int ans = 0;
        for(int i = 1; i <= xnum; i++)
        {
            //cout<<d[i]<<"\t";
            if(re.count(d[i]) == 0 && d[i] != 0)
                re.insert(d[i]),ans++;
        }
        //cout<<endl;
        printf("%d\n",ans);
    }
    return 0;
}