poj 2528 poster经典线段树+lazy+离散化

 #include<cstdio>
 #include<cstring>
 #include<algorithm>
 using namespace std;
 const int maxn=;
 #define lson l,m,rt<<1
 #define rson m+1,r,rt<<1|1
 int a[maxn];int b[maxn];int x[maxn*];int flag[maxn];
 int cor[maxn<<];
 int cnt=;
 int trans(int num,int l,int r)
 {
    // int m=(l+r)>>1;
   //  if(num==x[m]) return m;
   //  if(num>x[m]) return trans(num,m+1,r);
    // if(num<trans) return trans(num,l,m);
     while(l<=r)
     {
         int m=(l+r)>>;
         if(x[m]==num) return m;
         if(num>x[m]) l=m+;
         else r=m;
     }
     return -;
 }
 void pushdown(int rt)
 {
     if(cor[rt]!=-)
     {
         cor[rt<<]=cor[rt];
         cor[rt<<|]=cor[rt];
         cor[rt]=-;
     }
 }
 void update(int a,int b,int i,int l,int r,int rt)
 {
     if(a<=l&&b>=r)
     {
         cor[rt]=i;
         return;
     }
     pushdown(rt);
     int m=(r+l)>>;
     if(a<=m) update(a,b,i,lson);
     if(b>m) update(a,b,i,rson);
 }
 void query(int l,int r,int rt)
 {
     if(cor[rt]!=-)
     {
         if(!flag[cor[rt]])
         {
             cnt++;
             flag[cor[rt]]=;
         }
         return;
     }
     if(l==r) return;
     int m=(r+l)>>;
     query(lson);
     query(rson);
 }
 int main()
 {
     int cases,n;
     scanf("%d",&cases);
     while(cases--)
     {
         scanf("%d",&n);
         memset(cor,-,sizeof(cor));
         int pointer=;
         for(int i=;i<n;i++)
         {
             scanf("%d%d",&a[i],&b[i]);
             x[pointer++]=a[i];
             x[pointer++]=b[i];
         }
         sort(x+,x+pointer);
         int pointer2=;
         for(int i=;i<pointer;i++)
         {
             if(x[i]!=x[i-]) x[pointer2++]=x[i];
         }
         for(int i=pointer2-;i>=;i--)
         {
             if(x[i]!=x[i-]+) x[pointer2++]=x[i-]+;
         }
         sort(x,x+pointer2);
         for(int i=;i<n;i++)
         {
             int l=trans(a[i],,pointer2-);
             int r=trans(b[i],,pointer2-);
             update(l,r,i,,pointer2-,);
         }
         cnt=;
         memset(flag,,sizeof(flag));
         query(,pointer2-,);
         printf("%d\n",cnt);
     }
     return ;
 }