POJ 3481 Double Queue splay

// File Name: poj3481.cpp
// Author: darkdream
// Created Time: 2015年04月09日 星期四 14时41分43秒

#include<vector>
#include<list>
#include<map>
#include<set>
#include<deque>
#include<stack>
#include<bitset>
#include<algorithm>
#include<functional>
#include<numeric>
#include<utility>
#include<sstream>
#include<iostream>
#include<iomanip>
#include<cstdio>
#include<cmath>
#include<cstdlib>
#include<cstring>
#include<ctime>
#define LL long long
#define maxn 100005
using namespace std;

struct SplayTree{
int sz[maxn];
int ch[maxn][2];
int pre[maxn];
int root , top1,top2;
int ss[maxn],que[maxn];
inline void Rotate(int x, int f){
int y = pre[x];
push_down(y);
push_down(x);
ch[y][!f] = ch[x][f];
pre[ ch[x][f] ] = y  ;
pre[x] = pre[y];
if( pre[x] ) ch[ pre[y] ][ ch[pre[y]][1] == y ] = x;
ch[x][f] = y ;
pre[y] = x;
push_up(y);
}
inline void Splay(int x, int goal){
push_down(x);
while(pre[x] != goal){
if(pre[pre[x]] == goal){
Rotate(x,ch[pre[x]][0] == x);
}else{
int y = pre[x],z = pre[y];
int f = (ch[z][0] == y );
if(ch[y][f] == x){
Rotate(x,!f),Rotate(x,f);
}else{
Rotate(y,f),Rotate(x,f);
}
}
}
push_up(x);
if(goal == 0) root = x;
}
inline void RotateTo(int k ,int goal){
int x = root ;
push_down(x);
while(sz[ch[x][0]] != k){
if(k < sz[ch[x][0]]){
x = ch[x][0];
}else{
k -= (sz[ch[x][0]] + 1);
x = ch[x][1];
}
push_down(x);
}
Splay(x,goal);
}
inline void erase(int x)
{
int father = pre[x];
int head = 0 , tail =0 ;
for(que[tail++] = x ; head < tail ; head ++){
ss[top2++] = que[head];
if(ch[que[head]][0] )  que[tail ++] = ch[que[head]][0];
if(ch[que[head]][1] )  que[tail ++] = ch[que[head]][1];
}
ch[father][ch[father][1] == x] =0 ;
push_up(father);
}
inline void NewNode(int &x, int key ,int val){
if(top2) x = ss[--top2];
else x = ++top1;
ch[x][0] = ch[x][1] = pre[x] = 0 ;
sz[x] = 1;

vals[x] = val;
keys[x] = key ;
}

void init(){
ch[0][0] = ch[0][1] = sz[0] = pre[0] = 0 ;
root = top1 =0 ;
NewNode(root,0,0);
NewNode(ch[root][1],1e9,0);
sz[root] = 2;
pre[ch[root][1]] = root;
}
void push_up(int x){
sz[x] = 1 + sz[ch[x][0]] + sz[ch[x][1]];
}
void push_down(int x){

}
void insert(int key,int val){
int x = root ;
for(;;){
int f = (key > keys[x]);
if(ch[x][f] == 0 ){
NewNode(ch[x][f],key,val);
pre[ch[x][f]] = x;
Splay(ch[x][f],0);
return ;
}else{
x = ch[x][f];
}
}
}
void Del(int rank){
//printf("%d***\n",rank);
RotateTo(rank-1,0);
RotateTo(rank+1,root);
//    printf("%d %d\n",keys[root],keys[ch[root][1]]);
printf("%d\n",vals[ch[ch[root][1]][0]]);
erase(ch[ch[root][1]][0]);
push_up(root);
//    printf("****");
}
int keys[maxn];
int vals[maxn];
}spt;
int n ;
int key,val;
int main(){
spt.init();
while(scanf("%d",&n) != EOF && n )
{
int sz = spt.sz[spt.root];
if(n == 2 )
{
if(sz> 2){
spt.Del(sz-2);
}else{
printf("0\n");
}
}else if(n == 3){
if(sz> 2){
spt.Del(1);
}else{
printf("0\n");
}
}else{
scanf("%d %d",&val,&key);
spt.insert(key,val);
}
//     sz = spt.sz[spt.root];
//     printf("%d\n",sz);
}
return 0;
}