萌新10pts求调主席树
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萌新10pts求调主席树
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bktchizhi_fzh楼主2022/10/27 21:04
#include<iostream>
#include<cstdio>
#include<algorithm>
#define N 200005
using namespace std;
int n,m,a[N],b[N],tot,q,root[N],l,r,k;
struct Tree{
	int ls,rs,val,sum;
}tr[N*30];
int clone(int node){
	tot++;
	tr[tot]=tr[node];
	tr[tot].sum++;
	return tot;
}
int build(int node,int l,int r){
	node=++tot;
	if(l==r){
		return node;
	}
	int mid=(l+r)>>1;
	tr[node].ls=build(tr[node].ls,l,mid);
	tr[node].rs=build(tr[node].rs,mid+1,r);
	return node;
}
int update(int node,int l,int r,int x){
	node=clone(node);
	if(l==r)
		return node;
	int mid=(l+r)>>1;
	if(mid>=x)tr[node].ls=update(tr[node].ls,l,mid,x);
	else tr[node].rs=update(tr[node].rs,mid+1,r,x);
	return node;
}
int query(int x,int y,int l,int r,int k){
	if(l==r)return l;
	int mid=(l+r)>>1,uu=tr[tr[y].ls].sum-tr[tr[x].ls].sum;
	if(uu>=k)return query(tr[x].ls,tr[y].ls,l,mid,k);
	return query(tr[x].rs,tr[y].rs,mid+1,r,k-x);
}
int main(){
	scanf("%d%d",&n,&m);
	for(int i=1;i<=n;i++)scanf("%d",&a[i]),b[i]=a[i];
	sort(b+1,b+1+n);
	q=unique(b+1,b+1+n)-(b+1);
	root[0]=build(0,1,q);
	for(int i=1;i<=n;i++){
		int p=lower_bound(b+1,b+1+q,a[i])-b;
		root[i]=update(root[i-1],1,q,p);
	}
	for(int i=1;i<=m;i++){
		scanf("%d%d%d",&l,&r,&k);
		printf("%d\n",b[query(root[l-1],root[r],1,q,k)]);
	}
	return 0;
} 
2022/10/27 21:04
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