The bare tree is directly added to the Code.
If you don't understand the tree: http://blog.csdn.net/shiqi_614/article/details/8041390
#include <iostream>#include <cstdio>#include <cstring>#include <algorithm>using namespace std;#define MID(a,b) (a+((b-a)>>1))typedef long long LL;const int N=1e5+5;struct P_Tree{int n,order[N];int valu[20][N],num[20][N];LL sum[N],lsum[20][N],isum;void init(int len){n=len;sum[0]=0;for(int i=0;i<20;i++) valu[i][0]=0,num[i][0]=0,lsum[i][0]=0;for(int i=1;i<=n;i++){scanf("%d",&order[i]);valu[0][i]=order[i];sum[i]=sum[i-1]+order[i];}sort(order+1,order+1+n);build(1,n,0);}void build(int lft,int rht,int ind){if(lft==rht) return;int mid=MID(lft,rht);int same=mid-lft+1,ln=lft,rn=mid+1;for(int i=lft;i<=rht;i++)if(valu[ind][i]<order[mid]) same--;for(int i=lft;i<=rht;i++){int flag=0;if((valu[ind][i]<order[mid])||(valu[ind][i]==order[mid]&&same)){flag=1;valu[ind+1][ln++]=valu[ind][i];lsum[ind][i]=lsum[ind][i-1]+valu[ind][i];if(valu[ind][i]==order[mid]) same--;}else {valu[ind+1][rn++]=valu[ind][i];lsum[ind][i]=lsum[ind][i-1];}num[ind][i]=num[ind][i-1]+flag;}build(lft,mid,ind+1);build(mid+1,rht,ind+1);}int query(int st,int ed,int k,int lft,int rht,int ind){if(lft==rht) return valu[ind][lft];int mid=MID(lft,rht);int lx=num[ind][st-1]-num[ind][lft-1];int ly=num[ind][ed]-num[ind][st-1];int rx=st-1-lft+1-lx;int ry=ed-st+1-ly;if(ly>=k) return query(lft+lx,lft+lx+ly-1,k,lft,mid,ind+1);else {isum+=lsum[ind][ed]-lsum[ind][st-1];st=mid+1+rx;ed=mid+1+rx+ry-1;return query(st,ed,k-ly,mid+1,rht,ind+1);}}}tree;int main(){int n,m;while(scanf("%d%d",&n,&m)!=EOF){tree.init(n);for(int i=0;i<m;i++){int a,b,c;scanf("%d%d%d",&a,&b,&c);int res=tree.query(a,b,c,1,n,0);printf("%d\n",res);}}return 0;}