[bzoj3223]文艺平衡树(splay区间反转模板)

解题关键：splay模板题。

#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cstdlib>
#include<iostream>
#include<cmath>
using namespace std;
typedef long long ll;
const int N = ;

int ch[N][],par[N],val[N],cnt[N],size[N],rev[N],root,ncnt;
int n,m,x,y;

bool chk(int x){
    return ch[par[x]][]==x;
}

void pushup(int x){
    size[x]=size[ch[x][]]+size[ch[x][]]+cnt[x];
}

void pushdown(int x){
    if(rev[x]){
        swap(ch[x][],ch[x][]);//反转就是交换左右子树即可成立。
        rev[ch[x][]]^=;
        rev[ch[x][]]^=;
        rev[x]=;
    }
}

void rotate(int x){
    int y=par[x],z=par[y],k=chk(x),w=ch[x][k^];
    ch[y][k]=w;par[w]=y;
    ch[z][chk(y)]=x;par[x]=z;
    ch[x][k^]=y;par[y]=x;
    pushup(y);pushup(x);
}

void splay(int x,int goal=){
    while(par[x]!=goal){
        int y=par[x],z=par[y];
        if(z!=goal){
            if(chk(x)==chk(y)) rotate(y);
            else rotate(x);
        }
        rotate(x);
    }
    if(!goal) root=x;
}

void insert(int x){
    int cur=root,p=;
    while(cur&&val[cur]!=x){
        p=cur;
        cur=ch[cur][x>val[cur]];
    }
    if(cur){
        cnt[cur]++;
    }else{
        cur=++ncnt;
        if(p) ch[p][x>val[p]]=cur;
        ch[cur][]=ch[cur][]=;
        par[cur]=p;val[cur]=x;
        cnt[cur]=size[cur]=;
    }
    splay(cur);
}

void find(int x){
    int cur=root;
    if(!cur) return;
    while(ch[cur][x>val[cur]]&&x!=val[cur]){
        cur=ch[cur][x>val[cur]];
    }
    splay(cur);
}
//从1开始计数
int kth(int k){
    k++;
    int cur=root;
    while(){
        pushdown(cur);
        if(ch[cur][]&&k<=size[ch[cur][]]){
            cur=ch[cur][];
        }else if(k>size[ch[cur][]]+cnt[cur]){
            k-=size[ch[cur][]]+cnt[cur];
            cur=ch[cur][];
        }else{
            return cur;
        }
    }
}

int rnk(int x){
    find(x);
    if(val[root]>=x) return size[ch[root][]];
    else return size[ch[root][]]+cnt[root];
}

void reverse(int l,int r){
    int x=kth(l-),y=kth(r+);
    splay(x);splay(y,x);
    rev[ch[y][]]^=;
}

int pre(int x){
    find(x);
    if(val[root]<x) return root;
    int cur=ch[root][];
    while(ch[cur][]) cur=ch[cur][];
    return cur;
}

int succ(int x) {
    find(x);
    if(val[root]>x) return root;
    int cur=ch[root][];
    while(ch[cur][]) cur=ch[cur][];
    return cur;
}

void output(int x){
    pushdown(x);
    if(ch[x][]) output(ch[x][]);
    if(val[x]<=n&&val[x]>=) printf("%d ",val[x]);
    if(ch[x][]) output(ch[x][]);
}

void init(){
    insert(-2e9);
    insert(2e9);
}

int main(){
    init();
    scanf("%d%d",&n,&m);
    for(int i=;i<=n;i++) insert(i);
    while(m--){
        scanf("%d%d",&x,&y);
        reverse(x,y);
    }
    output(root);
    return ;
}