hdu 4417 2012杭州网络赛 划分树

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;

#define MAXN 100010
#define lson u<<1
#define rson u<<1|1

int sorted[MAXN],val[20][MAXN],Lnum[20][MAXN];
int n,q,high;

struct Node{
int lef,rig,mid;
}T[MAXN<<2];

void Build(int u,int l,int r,int d){
T[u].lef=l;
T[u].rig=r;
T[u].mid=(l+r)>>1;
if(l==r)return;
int mid=T[u].mid;
int lsame=mid-l+1;

for(int i=l;i<=r;i++){
if(val[d][i]<sorted[mid])lsame--;
}

int p=T[u].lef,q=T[u].mid+1,same=0;

for(int i=l;i<=r;i++){
if(i==l)Lnum[d][i]=0;
else Lnum[d][i]=Lnum[d][i-1];
if(val[d][i]<sorted[mid]){
val[d+1][p++]=val[d][i];
Lnum[d][i]++;
}
else if(val[d][i]>sorted[mid]){
val[d+1][q++]=val[d][i];
}
else {
if(same<lsame){
val[d+1][p++]=val[d][i];
Lnum[d][i]++;
same++;
}
else val[d+1][q++]=val[d][i];
}
}
Build(lson,l,mid,d+1);
Build(rson,mid+1,r,d+1);
}

int Query(int u,int l,int r,int d,int k){
if(l==r)return val[d][l];
else {
int n1,n2;
if(l==T[u].lef){n1=0;n2=Lnum[d][r];}
else {n1=Lnum[d][l-1];n2=Lnum[d][r]-n1;}
if(n2>=k){
int newl=T[u].lef+n1;
int newr=T[u].lef+n1+n2-1;
return Query(lson,newl,newr,d+1,k);
}
else {
int newl=T[u].mid+1+(l-T[u].lef-n1);
int newr=newl+(r-l+1-n2)-1;
return Query(rson,newl,newr,d+1,k-n2);
}
}
}

int bsearch(int l,int r,int key){
int mid;
int low=1,high=r-l+1;
while(low<high){
mid=low+(high-low)/2;
int tmp=Query(1,l,r,0,mid);
if(tmp<=key)low=mid+1;
else high=mid;
}
if(Query(1,l,r,0,low)>key)return low-1;
else return low;
}

int main(){

int t;
scanf("%d",&t);
for(int cas=1;cas<=t;cas++){
scanf("%d%d",&n,&q);
for(int i=1;i<=n;i++){
scanf("%d",&val[0][i]);
sorted[i]=val[0][i];
}
sort(sorted+1,sorted+1+n);
Build(1,1,n,0);
int l,r,h;
printf("Case %d:\n",cas);
while(q--){
scanf("%d%d%d",&l,&r,&h);
printf("%d\n",bsearch(l+1,r+1,h));
//Query(1,l+1,r+1,0,2);
}
}

}