bzoj 3223

splay

#include<bits/stdc++.h>using namespace std;const int maxn=100005;int ch[maxn][2],fa[maxn],vis[maxn],val[maxn],root=0,tot=0,s[maxn],n,m;inline void down(int x){    if(vis[x]){        int k1=ch[x][0],k2=ch[x][1];        swap(ch[k1][0],ch[k1][1]);vis[k1]^=1;        swap(ch[k2][0],ch[k2][1]);vis[k2]^=1;    }vis[x]=0;}inline void up(int x){s[x]=s[ch[x][0]]+s[ch[x][1]]+1;}void rotate(int x,int d){    int y=fa[x];down(y);down(x);    ch[y][d^1]=ch[x][d];    if(ch[x][d])fa[ch[x][d]]=y;    if(fa[y])ch[fa[y]][ch[fa[y]][1]==y]=x;    fa[x]=fa[y];    ch[x][d]=y;    fa[y]=x;    up(y);  }void splay(int x,int goal){    down(x);    while(fa[x]!=goal){        if(fa[fa[x]]==goal)rotate(x,ch[fa[x]][0]==x);        else{            int y=fa[x];            int d=ch[fa[y]][0]==y;            if(ch[y][d]==x){                rotate(x,d^1);                rotate(x,d);            }            else{                rotate(y,d);                rotate(x,d);            }        }    }up(x);    if(goal==0)root=x;}inline int pos(int x,int p){    while(x){down(x);             ///        int ss=s[ch[x][0]]+1;        if(p==ss)return x;        if(p>ss)x=ch[x][1],p-=ss;        else x=ch[x][0];    }}void build(int& x,int l,int r,int f){    if(l>r)return;    int mid=(l+r)>>1;    x=++tot;    fa[x]=f;    val[x]=mid;s[x]=1;    build(ch[x][0],l,mid-1,x);    build(ch[x][1],mid+1,r,x);    up(x);}void print(int x){    if(!x)return;    down(x);    print(ch[x][0]);      if(val[x]!=0 && val[x]!=n+1) printf("%d ",val[x]);        print(ch[x][1]);}int main(){//freopen("in.in","r",stdin);//freopen("out.out","w",stdout);    scanf("%d%d",&n,&m);    build(root,0,n+1,0);int l,r;    for(int i=1;i<=m;i++){        scanf("%d%d",&l,&r);l++,r++;        int x=pos(root,l-1);        splay(x,0);        int y=pos(root,r+1);        splay(y,root);        int v=ch[y][0];swap(ch[v][0],ch[v][1]);        vis[v]^=1;    }    print(root);printf("\n");}