[BZOJ3678]wangxz与OJ-[Splay一类的平衡树]

Description

传送门

Solution

直接splay搞定吧。。似乎非旋treap也ok？

我已经菜到模板题都写不出来了qaq

Code

#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
using namespace std;
int n,m,A[];
struct Splay
{
    int rt,cnt=;
    int ch[][],num[][],sz[],fa[];
    void pushup(int k){ sz[k]=sz[ch[k][]]+sz[ch[k][]]+num[k][]-num[k][]+;}
    void build(int &k,int l,int r)
    {
        k=++cnt;
        int mid=(l+r)/;
        num[k][]=num[k][]=A[mid];
        if (l<mid) build(ch[k][],l,mid-);
        if (mid<r) build(ch[k][],mid+,r);
        fa[ch[k][]]=fa[ch[k][]]=k;
        pushup(k);
    }
    void rotate(int x,int &rt)
    {
        int y=fa[x],k=ch[y][]==x;
        ch[y][k]=ch[x][k^];fa[ch[y][k]]=y;
        if (y==rt) rt=x;else ch[fa[y]][ch[fa[y]][]==y]=x;
        fa[x]=fa[y];
        fa[y]=x;ch[x][k^]=y;
        pushup(y);pushup(x);
    }
    void splay(int x,int &rt)
    {
        int y;
        while (x!=rt)
        {
            y=fa[x];
            if (y!=rt&&(ch[fa[y]][]==y)==(ch[y][]==x)) rotate(y,rt);
            rotate(x,rt);
        }
    }
    int work(int x,int k)
    {
        if (sz[ch[x][]]>=k) return work(ch[x][],k);
        if (sz[x]-sz[ch[x][]]<k)    return work(ch[x][],k-sz[x]+sz[ch[x][]]);
        k-=sz[ch[x][]];int son;
        if (k!=)
        {
            son=++cnt;
            num[son][]=num[x][];num[son][]=num[son][]+k-;
            num[x][]=num[son][]+;

            fa[son]=x;
            ch[son][]=ch[x][];
            ch[x][]=son;
            pushup(son);
            k=;
        }
        if (k!=num[x][]-num[x][]+)
        {
            son=++cnt;
            num[son][]=num[x][]+k;
            num[son][]=num[x][];
            num[x][]=num[son][]-;

            fa[son]=x;
            ch[son][]=ch[x][];
            ch[x][]=son;
            pushup(son);
        }
        return x;
    }
    void insert(int p,int a,int b)
    {
        int x1=work(rt,p),x2=work(rt,p+);
        splay(x1,rt);
        splay(x2,ch[x1][]);
        int son=++cnt;
        num[son][]=a;num[son][]=b;fa[son]=x2;
        ch[x2][]=son;
        sz[son]=b-a+;
        pushup(x2);
        pushup(x1);
    }
    void remove(int a,int b)
    {
        int x1=work(rt,a-),x2=work(rt,b+);
        splay(x1,rt);
        splay(x2,ch[x1][]);
        ch[x2][]=;
        pushup(x2);
        pushup(x1);
    }
    int query(int x,int q)
    {
        if (!x) return ;
        if (sz[ch[x][]]>=q) return query(ch[x][],q);
        if (sz[x]-sz[ch[x][]]>=q)
        {q-=sz[ch[x][]];return num[x][]+q-;}
        return query(ch[x][],q-sz[x]+sz[ch[x][]]);

    }
}splay;
int _type,p,a,b;
int main()
{
    scanf("%d%d",&n,&m);
    n++;
    for (int i=;i<=n;i++) scanf("%d",&A[i]);
    n++;
    splay.build(splay.rt,,n);
    for (int i=;i<=m;i++)
    {
        scanf("%d",&_type);
        if (!_type)
        {
            scanf("%d%d%d",&p,&a,&b);p++;
            splay.insert(p,a,b);
        }
        if (_type==)
        {
            scanf("%d%d",&a,&b);a++;b++;
            splay.remove(a,b);
        }
        if (_type==)
        {
            scanf("%d",&p);p++;
            printf("%d\n",splay.query(splay.rt,p));
        }
    }
}