劃分樹，對區間進行二分求 第mid 大的數 並且和 H比較即可。。

#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);
		}
	}

}