文艺平衡树（区间翻转）（Splay模板）

这篇blog写的吼啊

#include<cstdio>
#include<iostream>
#include<cstring>
using namespace std;
const int N=1e5+;
int fa[N],cnt[N],son[N][],size[N],key[N],v[N],type,root;
int n,m,a[N];
inline int read()
{
    int x=,f=;char ch=getchar();
    while(ch<''||ch>'')
    {if(ch=='-')f=-;ch=getchar();}
    while(ch>=''&&ch<='')
    {x=(x<<)+(x<<)+ch-'';ch=getchar();}
    return x*f;
}
bool judge(int x)
{
    return son[fa[x]][]==x;
}
void up(int x)
{
    size[x]=size[son[x][]]+size[son[x][]]+;
}
void down(int x)
{
    if(x&&v[x])
    {
        v[son[x][]]^=;
        v[son[x][]]^=;
        swap(son[x][],son[x][]);
        v[x]=;
    }
}
void rotate(int x)
{
    int old=fa[x],oldf=fa[old],lr=judge(x);
    down(old);down(x);
    son[old][lr]=son[x][lr^];fa[son[old][lr]]=old;
    son[x][lr^]=old;fa[old]=x;
    fa[x]=oldf;
    if(oldf)son[oldf][son[oldf][]==old]=x;
    up(old);up(x);
}
void splay(int x,int goal)
{
    for(int f;(f=fa[x])!=goal;rotate(x))
        if(fa[f]!=goal)
            rotate(judge(x)==judge(f)?f:x);
    if(!goal)root=x;
}
int build(int f,int l,int r)
{
    if(l>r)return ;
    int mid=l+r>>,now=++type;
    key[now]=a[mid];fa[now]=f;
    v[now]=;
    son[now][]=build(now,l,mid-);
    son[now][]=build(now,mid+,r);
    up(now);
    return now;
}
int getrank(int x)
{
    int now=root;
    while()
    {
        down(now);
        if(x<=size[son[now][]])now=son[now][];
        else
        {
            x-=size[son[now][]]+;
            if(!x)return now;
            now=son[now][];
        }
    }
}
void rev(int l,int r)
{
    l=getrank(l);
    r=getrank(r+);
    splay(l,);
    splay(r,l);
    down(root);
    v[son[son[root][]][]]^=;
}
void print(int now)
{
    down(now);
    if(son[now][])print(son[now][]);
    if(key[now]!=-0x3f3f3f3f&&key[now]!=0x3f3f3f3f)printf("%d ",key[now]);
    if(key[son[now][]])print(son[now][]);
}
int main()
{
    n=read();m=read();
    for(int i=;i<=n;i++)a[i+]=i;
    a[]=-0x3f3f3f3f;a[n+]=0x3f3f3f3f;
    root=build(,,n+);
    for(int i=;i<=m;i++)
    {
        int x=read(),y=read();
        rev(x,y);
    }
    print(root);
    return ;
}