POJ 1442 Black Box [treap]

#include<stdio.h>
#include<string.h>
#include<algorithm>
#include<math.h>
#include<iostream>
#include<stdlib.h>
#include<set>
#include<map>
#include<queue>
#include<vector>
#include<bitset>
#pragma comment(linker, "/STACK:1024000000,1024000000")
template <class T>
bool scanff(T &ret){ //Faster Input
char c; int sgn; T bit=0.1;
if(c=getchar(),c==EOF) return 0;
while(c!='-'&&c!='.'&&(c<'0'||c>'9')) c=getchar();
sgn=(c=='-')?-1:1;
ret=(c=='-')?0:(c-'0');
while(c=getchar(),c>='0'&&c<='9') ret=ret*10+(c-'0');
if(c==' '||c=='\n'){ ret*=sgn; return 1; }
while(c=getchar(),c>='0'&&c<='9') ret+=(c-'0')*bit,bit/=10;
ret*=sgn;
return 1;
}
#define inf 1073741823
#define llinf 4611686018427387903LL
#define PI acos(-1.0)
#define lth (th<<1)
#define rth (th<<1|1)
#define rep(i,a,b) for(ll i=a;i<=b;i++)
#define drep(i,a,b) for(ll i=a;i>=b;i--)
#define gson(i,root) for(ll i=ptx[root];~i;i=ed[i].next)
#define mem(x,val) memset(x,val,sizeof(x))
#define mkp(a,b) make_pair(a,b)
#define findx(x) lower_bound(b+1,b+1+bn,x)-b
#define pb(x) push_back(x)
using namespace std;
typedef long long ll;

int n,m;
int a[100100],ans[100100];
struct query{
int l,r,k,idx;
bool operator <(const query x)const{
if(l==x.l)return r<x.r;
return l<x.l;
}
}q[100100];

//treap
int tot,root;
struct node{
int size,val,rnd,l,r;
}t[100100];
void maintain(int x){
if(x<=0)return;
t[x].size=t[t[x].l].size+t[t[x].r].size+1;
}
void lturn(int &x){
int tmp=t[x].r;
t[x].r=t[tmp].l;
t[tmp].l=x;
maintain(x);
x=tmp;
}
void rturn(int &x){
int tmp=t[x].l;
t[x].l=t[tmp].r;
t[tmp].r=x;
maintain(x);
x=tmp;
}

void insert(int &x,int val){
if(x==0){
x=++tot;
t[x].val=val;
t[x].size=1;
t[x].rnd=rand();
t[x].l=t[x].r=0;
return;
}
else if(val<t[x].val){
insert(t[x].l,val);
if(t[t[x].l].rnd<t[x].rnd)rturn(x);
}
else{
insert(t[x].r,val);
if(t[t[x].r].rnd<t[x].rnd)lturn(x);
}
maintain(x);
}

void dele(int &x,int val){
if(val>t[x].val)dele(t[x].r,val);
else if(val<t[x].val)dele(t[x].l,val);
else{
if(t[x].l==0)x=t[x].r;
else if(t[x].r==0)x=t[x].l;
else{
if(t[t[x].l].rnd<t[t[x].r].rnd){
rturn(x);
dele(t[x].r,val);
}
else{
lturn(x);
dele(t[x].l,val);
}
}
}
maintain(x);
}

int findk(int x,int k){
int lsz=t[t[x].l].size;
int rsz=t[t[x].r].size;
if(k==lsz+1)return t[x].val;
if(k<=lsz)return findk(t[x].l,k);
return findk(t[x].r,k-lsz-1);
}

int exist(int x,int val){
while(x){
if(t[x].val==val)return 1;
else if(val>t[x].val)x=t[x].r;
else x=t[x].l;
}
return 0;
}

void init(){
tot=root=0;
rep(i,1,n)scanff(a[i]);
rep(i,1,m)scanff(q[i].l),scanff(q[i].r),scanff(q[i].k),q[i].idx=i;
sort(q+1,q+1+m);
}

void solve(){
int l=1,r=0;
rep(i,1,m){
for(;r<q[i].r;r++)insert(root,a[r+1]);
for(;l<q[i].l;l++)dele(root,a[l]);
ans[q[i].idx]=findk(root,q[i].k);
}
rep(i,1,m)
printf("%d\n",ans[i]);
}

main(){
while(scanf("%d%d",&n,&m)!=EOF){
init();
solve();
}
}