HYSBZ 1269テキストエディタsplay

#include<map>
#include<queue>
#include<stack>
#include<cmath>
#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#define INF 99999999
#define ll __int64
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
#define key_value ch[ch[root][1]][0]
using namespace std;
const int MAXN = 2200010;
int pre[MAXN],rev[MAXN],siz[MAXN],ch[MAXN][2],s[MAXN],tot1,tot2,root;
int n;
char a[MAXN],key[MAXN];
void Treavel(int x)
{
    if(x)
    {
        Treavel(ch[x][0]);
        printf(" %2d:  %2d   %2d   %2d size=%2d key=%2c rev=%2d pre=%2d
",x,ch[x][0],ch[x][1],pre[x],siz[x],key[x],rev[x],pre[x]);
        Treavel(ch[x][1]);
    }
}
void debug()
{
    printf("root:%d
",root);
    Treavel(root);
}
void Newnode(int &rt,int pa,int k)
{
    if(tot2){
        rt = s[tot2--];
    }
    else {
        rt = ++tot1;
    }
    pre[rt] = pa;
    siz[rt] = 1;
    key[rt] = k;
    rev[rt] = 0;
    ch[rt][0] = ch[rt][1] = 0;
}
void pushup(int rt)
{
    siz[rt] = siz[ch[rt][0]] + siz[ch[rt][1]] + 1;
}
void updata_rev(int rt)
{
    if(!rt)
        return;
    rev[rt] ^= 1;
    swap(ch[rt][0],ch[rt][1]);
}
void pushdown(int rt)
{
    if(rev[rt]){
        updata_rev(ch[rt][0]);
        updata_rev(ch[rt][1]);
        rev[rt] = 0;
    }
}
void build(int &rt,int l,int r,int pa)
{
    if(l > r)
        return ;
    int m = (l+r)/2;
    Newnode(rt,pa,a[m]);
    build(ch[rt][0],l,m-1,rt);
    build(ch[rt][1],m+1,r,rt);
    pushup(rt);
}
void Init()
{
    root = tot1 = tot2 = 0;
    key[root] = pre[root] = rev[root] = siz[root] = 0;
    ch[root][0] = ch[root][1] = 0;
    Newnode(root,0,0);
    Newnode(ch[root][1],root,0);
    pushup(ch[root][1]);
    pushup(root);
}
void Rotate(int rt,int kind)
{
    int y = pre[rt];
    pushdown(y);
    pushdown(rt);
    ch[y][!kind] = ch[rt][kind];
    pre[ch[rt][kind]] = y;
    if(pre[y]){
        ch[pre[y]][ch[pre[y]][1]==y] = rt;
    }
    pre[rt] = pre[y];
    ch[rt][kind] = y;
    pre[y] = rt;
    pushup(y);
}
void splay(int rt,int goal)
 {
    pushdown(rt);
    while(pre[rt] != goal)
    {
        if(pre[pre[rt]] == goal){
            pushdown(pre[rt]);
            pushdown(rt);
            Rotate(rt,ch[pre[rt]][0]==rt);
        }
        else {
            pushdown(pre[pre[rt]]);
            pushdown(pre[rt]);
            pushdown(rt);
            int y = pre[rt];
            int kind = ch[pre[y]][0]==y;
            if(ch[y][kind] == rt){
                Rotate(rt,!kind);
                Rotate(rt,kind);
            }
            else {
                Rotate(y,kind);
                Rotate(rt,kind);
            }
        }
    }
    if(goal == 0)
        root = rt;
    pushup(rt);
}
int Get_kth(int rt,int k)
{
    pushdown(rt);
    int t = siz[ch[rt][0]] + 1;
    if(t == k){
        return rt;
    }
    else if(t > k){
        return Get_kth(ch[rt][0],k);
    }
    else {
        return Get_kth(ch[rt][1],k-t);
    }
}
int Get_next(int rt)
{
    pushdown(rt);
    int tmp = ch[rt][1];
    while(ch[tmp][0]){
        tmp = ch[tmp][0];
        pushdown(tmp);
    }
    return tmp;
}
int Get_pre(int rt)
{
    pushdown(rt);
    int tmp = ch[rt][0];
    while(ch[tmp][1]){
        tmp = ch[tmp][1];
        pushdown(tmp);
    }
    return tmp;
}
void erase(int rt)
{
    if(!rt)
        return;
    s[++tot2] = rt;
    erase(ch[rt][0]);
    erase(ch[rt][1]);
}
int main()
{
    int i,j;
    while(~scanf("%d",&n))
    {
        Init();
        char c[20];
        //debug();
        while(n--)
        {
            scanf("%s",c);
            if(c[0] == 'I'){
                int len;
                scanf("%d",&len);
                getchar();
                gets(a);
                splay(Get_next(root),root);
                build(key_value,0,len-1,ch[root][1]);
                pushup(ch[root][1]);
                pushup(root);
                //debug();
            }
            else if(c[0] == 'D'){
                int x;
                scanf("%d",&x);
                int ret = siz[ch[root][0]] + 1;
                splay(Get_kth(root,ret+x+1),root);
                erase(key_value);
                pre[key_value] = 0;
                key_value = 0;
                pushup(ch[root][1]);
                pushup(root);
                //debug();
            }
            else if(c[0] == 'R'){
                int x;
                scanf("%d",&x);
                int ret = siz[ch[root][0]] + 1;
                splay(Get_kth(root,ret+x+1),root);
                updata_rev(key_value);
                pushup(ch[root][1]);
                pushup(root);
                //debug();
            }
            else if(c[0] == 'G'){
                printf("%c
",key[Get_next(root)]);
            }
            else if(c[0] == 'M'){
                int x;
                scanf("%d",&x);
                splay(Get_kth(root,x+1),0);
                //debug();
            }
            else if(c[0] == 'P'){
                splay(Get_pre(root),0);
                //debug();
            }
            else {
                splay(Get_next(root),0);
                //debug();
            }
        }
    }
}