bzoj 1818: [Cqoi2010]内部白点

 #include<cstdio>
 #include<iostream>
 #include<algorithm>
 using namespace std;
 struct data
 {
     int x,y,k,r;
 }a[];
 struct dat
 {
     int x,y;
 }b[];
 bool cmp(dat a1,dat a2)
 {
     if(a1.x==a2.x)
       return a1.y<a2.y;
     return a1.x<a2.x;
 }
 int n,h[],h1[],shu[],cnt,ans;
 void jia1(int a1,int a2)
 {
     cnt++;
     a[cnt].x=lower_bound(h+,h+h[]+,b[a1].x)-h;
     a[cnt].y=b[a1].y;
     a[cnt].k=;
     cnt++;
     a[cnt].x=a[cnt-].x;
     a[cnt].y=b[a2].y;
     a[cnt].k=-;
 }
 bool cmp1(dat a1,dat a2)
 {
     if(a1.y==a2.y)
       return a1.x<a2.x;
     return a1.y<a2.y;
 }
 void jia2(int a1,int a2)
 {
     cnt++;
     a[cnt].y=b[a1].y;
     a[cnt].x=lower_bound(h+,h+h[]+,b[a1].x)-h;
     a[cnt].r=lower_bound(h+,h+h[]+,b[a2].x)-h;
 }
 bool cmp2(data a1,data a2)
 {
     if(a1.y==a2.y)
       return a1.k<a2.k;
     return a1.y<a2.y;
 }
 int zhao(int a1)
 {
     int sum=;
     for(;a1;a1-=a1&-a1)
       sum+=shu[a1];
     return sum;
 }
 void gai(int a1,int a2)
 {
     for(;a1<=h[];a1+=a1&-a1)
       shu[a1]+=a2;
     return;
 }
 int main()
 {
     scanf("%d",&n);
     for(int i=;i<=n;i++)
       scanf("%d%d",&b[i].x,&b[i].y);
     for(int i=;i<=n;i++)
       h1[i]=b[i].x;
     sort(h1+,h1++n);
     h[]=h1[];
     h[]=;
     for(int i=;i<=n;i++)
       if(h1[i]!=h1[i-])
         {
             h[]++;
             h[h[]]=h1[i];
         }
     sort(b+,b+n+,cmp);
     for(int i=;i<=n;i++)
       if(b[i].x==b[i-].x)
         jia1(i-,i);
     sort(b+,b+n+,cmp1);
     for(int i=;i<=n;i++)
       if(b[i].y==b[i-].y)
         jia2(i-,i);
     sort(a+,a+cnt+,cmp2);
     for(int i=;i<=cnt;i++)
       if(a[i].k==)
         ans+=zhao(a[i].r-)-zhao(a[i].x);
       else
         gai(a[i].x,a[i].k);
     printf("%d",ans+n);
     return ;
 }

 #include<cstdio>
 #include<iostream>
 #include<algorithm>
 using namespace std;
 struct data
 {
     int x,y,k,r;
 }a[];
 struct dat
 {
     int x,y;
 }b[];
 bool cmp(dat a1,dat a2)
 {
     if(a1.x==a2.x)
       return a1.y<a2.y;
     return a1.x<a2.x;
 }
 int n,h[],h1[],shu[],cnt,ans;
 void jia1(int a1,int a2)
 {
     cnt++;
     a[cnt].x=lower_bound(h+,h+h[]+,b[a1].x)-h;
     a[cnt].y=b[a1].y;
     a[cnt].k=;
     cnt++;
     a[cnt].x=a[cnt-].x;
     a[cnt].y=b[a2].y;
     a[cnt].k=-;
 }
 bool cmp1(dat a1,dat a2)
 {
     if(a1.y==a2.y)
       return a1.x<a2.x;
     return a1.y<a2.y;
 }
 void jia2(int a1,int a2)
 {
     cnt++;
     a[cnt].y=b[a1].y;
     a[cnt].x=lower_bound(h+,h+h[]+,b[a1].x)-h;
     a[cnt].r=lower_bound(h+,h+h[]+,b[a2].x)-h;
 }
 bool cmp2(data a1,data a2)
 {
     if(a1.y==a2.y)
       return a1.k<a2.k;
     return a1.y<a2.y;
 }
 int zhao(int a1)
 {
     int sum=;
     for(;a1;a1-=a1&-a1)
       sum+=shu[a1];
     return sum;
 }
 void gai(int a1,int a2)
 {
     for(;a1<=h[];a1+=a1&-a1)
       shu[a1]+=a2;
     return;
 }
 int main()
 {
     scanf("%d",&n);
     for(int i=;i<=n;i++)
       scanf("%d%d",&b[i].x,&b[i].y);
     for(int i=;i<=n;i++)
       h1[i]=b[i].x;
     sort(h1+,h1++n);
     h[]=h1[];
     h[]=;
     for(int i=;i<=n;i++)
       if(h1[i]!=h1[i-])
         {
             h[]++;
             h[h[]]=h1[i];
         }
     sort(b+,b+n+,cmp);
     for(int i=;i<=n;i++)
       if(b[i].x==b[i-].x)
         jia1(i-,i);
     sort(b+,b+n+,cmp1);
     for(int i=;i<=n;i++)
       if(b[i].y==b[i-].y)
         jia2(i-,i);
     sort(a+,a+cnt+,cmp2);
     for(int i=;i<=cnt;i++)
       if(a[i].k==)
         ans+=zhao(a[i].r-)-zhao(a[i].x);
       else
         gai(a[i].x,a[i].k);
     printf("%d",ans+n);
     return ;
 }

将点拆成横线与点，用树状数组维护。