"Tree-like array" "Weight-value chunking" bzoj2352 Stars

Classic problem: Two-dimensional partial ordering. The number of points at the bottom left of each point, given the n points in a plane.

Because all points already have Y as the first keyword, x is ordered for the second keyword, so we do it in read order, just need to calculate how many points the X coordinate is less than <= a point.

This is what is said: n-dimensional partial order, one-dimensional ordering, two-dimensional tree-like array, three-dimensional partition Or tree-shaped array set of balance tree ...

< law one > tree-like array.

1#include <cstdio>2#include <algorithm>3#include <iostream>4 using namespacestd;5 struct Point6 {7     intx, y;8 };9 intn,d[3200001],ji[1500001],m;TenPoint star[1500001]; One BOOLcmpConstPoint &a,ConstPoint &b) A { -     if(a.x<b.x) -       return true; the     Else if(a.x>b.x) -       return false; -     Else if(a.y<b.y) -       return true; +     return false; - } + intLowbit (intx) A { at     returnx& (-x); - } - voidUpdateintXintDelta) - { -      for(; x<=m;x+=lowbit (x)) -d[x]+=Delta; in } - intGetsum (intx) to { +     intres=0; -      for(;x>0; x-=lowbit (x)) theres+=D[x]; *     returnRes; $ }Panax Notoginseng intMain () - { thescanf"%d",&n); +      for(intI=1; i<=n;i++) A       { thescanf"%d%d",&star[i].x,&star[i].y); +star[i].y++; -m=Max (M,STAR[I].Y); $       } $      for(intI=1; i<=n;i++) -       { -Update (STAR[I].Y,1); theJi[getsum (STAR[I].Y)-1]++; -       }Wuyi      for(intI=0; i<n;i++) theprintf"%d\n", Ji[i]); -     return 0; Wu}

< method two > Weight sub-block. I'd say it's nearly a fold faster than a tree-shaped array?

1#include <cstdio>2#include <cmath>3#include <algorithm>4 using namespacestd;5 intn,x[15001],y[15001],limit,r[ $],l[ $],num[33000],sumv[ $],sz,sum,rank[33000],b[33000];6 voidMakeblock ()7 {8Sz= (int) sqrt (Double) LIMIT);if(!SZ) sz=1; r[0]=-1;9      for(sum=1; sum*sz<limit;sum++)Ten       { Onel[sum]=r[sum-1]+1; Ar[sum]=sum*sz; -            for(inti=l[sum];i<=r[sum];i++) num[i]=sum; -       } thel[sum]=r[sum-1]+1; -r[sum]=LIMIT; -      for(inti=l[sum];i<=r[sum];i++) num[i]=sum; - } + intQueryConst int&V) - { +     intCnt=0; A      for(intI=1; i<num[v];i++) cnt+=Sumv[i]; at      for(inti=l[num[v]];i<=v;i++) cnt+=B[i]; -++B[V]; ++Sumv[num[v]]; -     returnCNT; - } - intMain () - { inscanf"%d",&n); -      for(intI=1; i<=n;i++) to       { +scanf"%d%d",&x[i],&y[i]); -limit=Max (limit,x[i]); the } makeblock (); *      for(intI=1; i<=n;i++) + +rank[query (X[i]); $      for(intI=0; i<n;i++) printf ("%d\n", Rank[i]);Panax Notoginseng     return 0; -}

"Tree-like array" "Weight-value chunking" bzoj2352 Stars