luoguP3391[模板]文艺平衡树(Splay) 题解

#include<iostream>
#include<cstdlib>
#include<cstdio>
#include<cmath>
#include<cstring>
#include<iomanip>
#include<algorithm>
#include<ctime>
#include<queue>
#include<stack>
#define rg register
#define lst long long
#define N 1000050
using namespace std;

int n,m,tot,root;
struct Node{
    int ch[2];
    int v,fa;
    int size;
    int lazy;
}ljl[N];

inline int read()
{
    rg int s=0,m=1;char ch=getchar();
    while(ch!=‘-‘&&(ch<‘0‘||ch>‘9‘))ch=getchar();
    if(ch==‘-‘)m=0,ch=getchar();
    while(ch>=‘0‘&&ch<=‘9‘)s=(s<<3)+(s<<1)+ch-‘0‘,ch=getchar();
    return m?s:-s;
}

inline void Pushup(rg int now)
{
    ljl[now].size=ljl[ljl[now].ch[0]].size+ljl[ljl[now].ch[1]].size+1;
}

inline void Pushdown(rg int now)
{
    if(ljl[now].lazy)
    {
        ljl[ljl[now].ch[0]].lazy^=1;
        ljl[ljl[now].ch[1]].lazy^=1;
        swap(ljl[now].ch[0],ljl[now].ch[1]);
        ljl[now].lazy=0;
    }
}

inline void rotate(rg int x)
{
    rg int y=ljl[x].fa,z=ljl[y].fa;
    rg int k=ljl[y].ch[1]==x;
    ljl[z].ch[ljl[z].ch[1]==y]=x;
    ljl[x].fa=z;
    ljl[y].ch[k]=ljl[x].ch[k^1];
    ljl[ljl[x].ch[k^1]].fa=y;
    ljl[x].ch[k^1]=y;
    ljl[y].fa=x;
    Pushup(x),Pushup(y);
}

inline void splay(rg int x,rg int goal)
{
    while(ljl[x].fa!=goal)
    {
        rg int y=ljl[x].fa,z=ljl[y].fa;
        if(z!=goal)(x==ljl[y].ch[0])^(y==ljl[z].ch[0])?rotate(x):rotate(y);
        rotate(x);
    }
    if(goal==0)root=x;
}

inline void Insert(rg int x)
{
    int now=root,fa=0;
    while(now)fa=now,now=ljl[now].ch[x>ljl[now].v];
    now=++tot;
    if(fa)ljl[fa].ch[x>ljl[now].v]=now;
    ljl[now].ch[0]=ljl[now].ch[1]=0;
    ljl[now].v=x;ljl[now].fa=fa;
    ljl[now].size=1;
    splay(now,0);
}

inline int Kth(rg int x)
{
    rg int now=root;
    while(233)
    {
        Pushdown(now);
        if(x>ljl[ljl[now].ch[0]].size+1)
            x-=ljl[ljl[now].ch[0]].size+1,now=ljl[now].ch[1];
        else if(ljl[ljl[now].ch[0]].size>=x)now=ljl[now].ch[0];
        else return now;
    }
}

inline void Work(rg int le,rg int ri)
{
    rg int qq=Kth(le);
    rg int hj=Kth(ri+2);
    splay(qq,0),splay(hj,qq);
    ljl[ljl[ljl[root].ch[1]].ch[0]].lazy^=1;
}

void Write(rg int now)
{
    Pushdown(now);
    if(ljl[now].ch[0])Write(ljl[now].ch[0]);
    if(ljl[now].v>1&&ljl[now].v<n+2)printf("%d ",ljl[now].v-1);
    if(ljl[now].ch[1])Write(ljl[now].ch[1]);
}

int main()
{
    n=read(),m=read();
    for(rg int i=1;i<=n+2;++i)Insert(i);
    for(rg int i=1;i<=m;++i)
    {
        rg int le=read(),ri=read();
        Work(le,ri);
    }
    Write(root);
    return 0;
}