D

题意贴海报最后可以看到多少海报
思路：离散化大区间其中[1,4] [5,6]不能离散化成[1,2] [2,3]因为这样破坏了他们的非相邻关系每次离散化区间 [x,y]时把y+1点也加入就行了
注：参考了上海全能王csl的博客！
  1 #include<cstdio>
  2 #include<algorithm>
  3 #include<set>
  4 #include<vector>
  5 #include<cstring>
  6 #include<iostream>
  7 using namespace std;
  8 #define X first 
  9 #define Y second 
 10 const int maxn=200000+5;
 11 pair<int,int>a[maxn*2];
 12 vector<int>v;
 13 struct Node{
 14     int l,r;
 15     int col;
 16     int lazy;
 17     void update(int x){
 18         col=x;
 19         lazy=x;
 20     }
 21 }tree[maxn*6];
 22 bool vis[maxn*2];
 23 /*void push_up(int x){
 24     if(tree[x<<1].col!=tree[x<<1|1].col||tree[x<<1].col==-1||tree[x<<1|1].col==-1)tree[x].col=-1;
 25 }*/
 26 
 27 void build(int x,int l,int r){
 28     tree[x].l=l,tree[x].r=r;
 29     tree[x].col=-1;    
 30     if(l==r){
 31         return ;
 32     }
 33     else {
 34         int mid=l+r>>1;
 35         build(x<<1,l,mid);
 36         build(x<<1|1,mid+1,r);
 37     }
 38 }
 39 
 40 void push_down(int x){
 41     if(tree[x].col==-1)return;
 42     tree[x<<1].col=tree[x<<1|1].col=tree[x].col;
 43     tree[x].col=-1;
 44 }
 45 void update(int x,int l,int r,int val){
 46     int L=tree[x].l,R=tree[x].r;
 47     if(l<=L&&R<=r){
 48         tree[x].col=val;
 49         return ;
 50     }
 51     else {
 52         push_down(x);
 53         int mid=(L+R)>>1;
 54         if(l<=mid)update(x<<1,l,r,val);
 55         if(mid<r)update(x<<1|1,l,r,val);
 56     //    pudh_up(x);单点查询不需要合并
 57     }
 58 }
 59 long long query(int x,int a){
 60     int L=tree[x].l,R=tree[x].r;
 61     if(L==R)return tree[x].col;
 62     push_down(x);
 63     int mid=L+R>>1;
 64     if(mid>=a)query(x<<1,a);
 65     else if(mid<a)query(x<<1|1,a);
 66 }
 67 
 68 int main(){
 69     int t;
 70     scanf("%d",&t);
 71     while(t--){
 72         int n;
 73         memset(vis,0,sizeof(vis));
 74         scanf("%d",&n);
 75         for(int i=0;i<n;i++){
 76             scanf("%d%d",&a[i].X,&a[i].Y);
 77             v.push_back(a[i].X);
 78             v.push_back(a[i].Y);
 79             v.push_back(a[i].Y+1);
 80         }
 81     sort(v.begin(),v.end());
 82     int num=unique(v.begin(),v.end())-v.begin();
 83     for(int i=0;i<n;i++){
 84       a[i].X = lower_bound(v.begin(), v.begin() + num, a[i].X) - v.begin() + 1;
 85       a[i].Y = lower_bound(v.begin(), v.begin() + num, a[i].Y) - v.begin() + 1;
 86     }
 87     build(1,1,num);
 88     for(int i=0;i<n;i++){
 89         update(1,a[i].X,a[i].Y,i+1);
 90     }
 91     int ans=0;
 92     for(int i=1;i<=num;i++){
 93         int col=query(1,i);
 94     //    cout<<col<<endl;
 95         if(col!=-1&&vis[col]==0){
 96             vis[col]=1;
 97             ans++;
 98         }
 99     }
100     printf("%d
",ans);
101     }
102     return 0;
103 }