[bzoj1227] [SDOI2009]虔诚的墓主人

 1 #include<cstdio>
 2 #include<iostream>
 3 #include<cstring>
 4 #include<algorithm>
 5 #define ui unsigned int
 6 using namespace std;
 7 const int maxn=100233,mxnode=maxn<<1;
 8 struct zs{int v,id;}X[maxn],Y[maxn];
 9 struct poi{int x,y;}a[maxn];
10 int lc[mxnode],rc[mxnode],num1[mxnode],num2[mxnode],tot;
11 int mp[maxn],st[maxn],top;
12 ui sm[mxnode],ans,SM,c[maxn][11];
13 int i,j,k,n,m,kk,L,R,P;
14   
15   
16 int ra,fh;char rx;
17 inline int read(){
18     rx=getchar(),ra=0,fh=1;
19     while((rx<‘0‘||rx>‘9‘)&&rx!=‘-‘)rx=getchar();
20     if(rx==‘-‘)fh=-1,rx=getchar();
21     while(rx>=‘0‘&&rx<=‘9‘)ra*=10,ra+=rx-48,rx=getchar();return ra*fh;
22 }
23 void build(int a,int b){
24     int x=++tot;
25     if(a==b){num2[x]=mp[a];return;}
26     int mid=a+b>>1;
27     lc[x]=tot+1,build(a,mid),rc[x]=tot+1,build(mid+1,b);
28 }
29 void change(int x,int a,int b){
30     if(a==b){
31         num1[x]++,num2[x]--,sm[x]=c[num1[x]][kk]*c[num2[x]][kk];
32         return;
33     }
34     int mid=a+b>>1;
35     if(P<=mid)change(lc[x],a,mid);else change(rc[x],mid+1,b);
36     sm[x]=sm[lc[x]]+sm[rc[x]];
37 }
38 void query(int x,int a,int b){
39     if(L<=a&&R>=b){
40         SM+=sm[x];return;
41     }
42     int mid=a+b>>1;
43     if(L<=mid)query(lc[x],a,mid);
44     if(R>mid)query(rc[x],mid+1,b);
45 }
46  
47  
48 bool cmp(zs a,zs b){return a.v<b.v;}
49 bool cmpa(poi a,poi b){return a.x<b.x||(a.x==b.x&&a.y<b.y);}
50 int main(){
51     n=read(),m=read();
52     n=read();
53     for(i=1;i<=n;i++)X[i].v=read(),Y[i].v=read(),X[i].id=Y[i].id=i;
54     kk=read();
55     for(i=0;i<=n;i++)c[i][0]=1;
56     for(i=1;i<=n;i++)for(j=1;j<=kk;j++)c[i][j]=c[i-1][j]+c[i-1][j-1];
57 //  for(i=1;i<=n;i++)printf("C(%d %d)  %u\n",i,kk,c[i][kk]);return 233;
58      
59     sort(X+1,X+1+n,cmp),sort(Y+1,Y+1+n,cmp);int cntx=0,cnty=0;
60     for(i=1;i<=n;a[X[i].id].x=cntx,i++)
61         if(X[i].v!=X[i-1].v||i==1)cntx++;
62     for(i=1;i<=n;a[Y[i].id].y=cnty,mp[cnty]++,i++)
63         if(Y[i].v!=Y[i-1].v||i==1)cnty++;
64     sort(a+1,a+1+n,cmpa);
65     build(1,cnty);
66      
67     for(i=1;i<=n;){
68         int r=i-1,top=0;
69         while(r<n&&a[r+1].x==a[i].x)r++,st[++top]=P=a[r].y,change(1,1,cnty);//,printf("   %d",P);puts("");
70         if(top>=(kk<<1))
71         for(j=kk;j<=top-kk;j++)if(st[j]+1<st[j+1])
72             SM=0,L=st[j]+1,R=st[j+1]-1,query(1,1,cnty),
73             ans+=SM*c[j][kk]*c[top-j][kk];
74         i=r+1;
75     }
76     printf("%d\n",ans<<1>>1);
77 }