【模板】平衡樹Splay
阿新 • • 發佈:2020-08-15
#include<algorithm> #include<iostream> #include<cstring> #include<iomanip> #include<sstream> #include<cstdio> #include<string> #include<vector> #include<bitset> #include<queue> #include<cmath> #include<stack> #include<set> #include<map> #define rep(i,x,n) for(int i=x;i<=n;i++) #define per(i,n,x) for(int i=n;i>=x;i--) #define sz(a) int(a.size()) #define rson mid+1,r,p<<1|1 #define pii pair<int,int> #define lson l,mid,p<<1 #define ll long long #define pb push_back #define mp make_pair #define se second #define fi first using namespace std; const double eps=1e-8; const int mod=1e9+7; const int N=1e5+10; const int inf=1e9; int n; int rt,tot,ch[N][2],sz[N],val[N],fa[N],cnt[N]; struct Splay{ void maintain(int x){ sz[x]=sz[ch[x][0]]+sz[ch[x][1]]+cnt[x]; } bool get(int x){ return x==ch[fa[x]][1]; } void clear(int x){ ch[x][0]=ch[x][1]=fa[x]=val[x]=sz[x]=cnt[x]=0; } void rotate(int x){ int y=fa[x],z=fa[y],chk=get(x); ch[y][chk]=ch[x][chk^1]; fa[ch[x][chk^1]]=y; ch[x][chk^1]=y; fa[y]=x; fa[x]=z; if(z) ch[z][ y==ch[z][1] ]=x; maintain(x); maintain(y); } void splay(int x){ for(int f=fa[x];f=fa[x],f;rotate(x)){ if(fa[f]) rotate(get(x)==get(f)?f:x); } rt=x; } void ins(int k){ if(!rt){ val[++tot]=k; cnt[tot]++; rt=tot; maintain(rt); return; } int cnr=rt,f=0; while(1){ if(val[cnr]==k){ cnt[cnr]++; maintain(cnr); maintain(f); splay(cnr); break; } f=cnr; cnr=ch[cnr][val[cnr]<k]; if(!cnr){ val[++tot]=k; cnt[tot]++; fa[tot]=f; ch[f][val[f]<k]=tot; maintain(tot); maintain(f); splay(tot); break; } } } int rk(int k){ int res=0,cnr=rt; while(1){ if(k<val[cnr]){ cnr=ch[cnr][0]; }else{ res+=sz[ch[cnr][0]]; if(k==val[cnr]){ splay(cnr); return res+1; } res+=cnt[cnr]; cnr=ch[cnr][1]; } } } int kth(int k){ int cnr=rt; while(1){ if(ch[cnr][0]&&sz[ch[cnr][0]]>=k){ cnr=ch[cnr][0]; }else{ k-=cnt[cnr]+sz[ch[cnr][0]]; if(k<=0){ splay(cnr); return val[cnr]; } cnr=ch[cnr][1]; } } } int pre(){ int cnr=ch[rt][0]; while(ch[cnr][1]) cnr=ch[cnr][1]; splay(cnr); return cnr; } int nxt(){ int cnr=ch[rt][1]; while(ch[cnr][0]) cnr=ch[cnr][0]; splay(cnr); return cnr; } void del(int k){ rk(k); if(cnt[rt]>1){ cnt[rt]--; maintain(rt); return; } if(!ch[rt][0]&&!ch[rt][1]){ clear(rt); rt=0; return; } if(!ch[rt][0]){ int cnr=rt; rt=ch[rt][1]; fa[rt]=0; clear(cnr); return; } if(!ch[rt][1]){ int cnr=rt; rt=ch[rt][0]; fa[rt]=0; clear(cnr); return; } int cnr=rt,x=pre(); splay(x); fa[ch[cnr][1]]=x; ch[x][1]=ch[cnr][1]; clear(cnr); maintain(rt); } }S; int main(){ //ios::sync_with_stdio(false); //freopen("in","r",stdin); scanf("%d",&n); rep(i,1,n){ int opt,x; scanf("%d%d",&opt,&x); if(opt==1){ S.ins(x); }else if(opt==2){ S.del(x); }else if(opt==3){ S.ins(x); printf("%d\n",S.rk(x)); S.del(x); }else if(opt==4){ printf("%d\n",S.kth(x)); }else if(opt==5){ S.ins(x); printf("%d\n",val[S.pre()]); S.del(x); }else{ S.ins(x); printf("%d\n",val[S.nxt()]); S.del(x); } } return 0; }