luogu3369 【模板】普通平衡树（Treap/SBT） treap splay

treap做法，参考hzwer的博客

#include <iostream>
#include <cstdlib>
#include <cstdio>
using namespace std;
int n, opt, uu, rot, cnt, ans;
struct Treap{
    int siz[100005], hav[100005], val[100005], rnd[100005], l[100005], r[100005];
    void upd(int x){
        siz[x] = siz[l[x]] + siz[r[x]] + hav[x];
    }
    void lRotate(int &k){
        int t=r[k]; r[k] = l[t]; l[t] = k;
        siz[t] = siz[k]; upd(k); k = t;
    }
    void rRotate(int &k){
        int t=l[k]; l[k] = r[t]; r[t] = k;
        siz[t] = siz[k]; upd(k); k = t;
    }
    void insert(int &k, int x){
        if(!k){
            k = ++cnt; siz[k] = hav[k] = 1;
            val[k] = x; rnd[k] = rand();
			return ;
        }
        siz[k]++;
        if(val[k]==x)	hav[k]++;
        else if(val[k]<x){
            insert(r[k], x);
            if(rnd[r[k]]<rnd[k])	lRotate(k);
        }
        else{
            insert(l[k], x);
            if(rnd[l[k]]<rnd[k])	rRotate(k);
        }
    }
    void shanchu(int &k, int x){
        if(!k)	return ;
        if(val[k]==x){
            if(hav[k]>1){
                hav[k]--; siz[k]--;
                return ;
            }
            else if(l[k]*r[k]==0)	k = l[k] + r[k];
            else if(rnd[l[k]]>rnd[r[k]])
                lRotate(k), shanchu(k, x);
            else
                rRotate(k), shanchu(k, x);
        }
        else if(val[k]<x)	siz[k]--, shanchu(r[k], x);
        else	siz[k]--, shanchu(l[k], x);
    }
    int queryRank(int k, int x){
        if(x<val[k])	return queryRank(l[k], x);
        else if(x>val[k])	return queryRank(r[k], x)+siz[l[k]]+hav[k];
        else	return siz[l[k]]+1;
    }
    int queryNum(int k, int x){
        if(x<=siz[l[k]])	return queryNum(l[k], x);
        else if(x>siz[l[k]]+hav[k])	return queryNum(r[k], x-siz[l[k]]-hav[k]);
        else	return val[k];
    }
    void queryPre(int k, int x){
        if(!k)	return ;
        if(val[k]<x)	ans = k, queryPre(r[k], x);
        else	queryPre(l[k], x);
    }
    void queryNxt(int k, int x){
        if(!k)	return ;
        if(val[k]>x)	ans = k, queryNxt(l[k], x);
        else	queryNxt(r[k], x);
    }
}treap;
int main(){
    cin>>n;
    while(n--){
        scanf("%d %d", &opt, &uu);
        switch(opt){
            case 1:	treap.insert(rot, uu); break;
            case 2: treap.shanchu(rot, uu); break;
            case 3:	printf("%d\n", treap.queryRank(rot, uu)); break;
            case 4:	printf("%d\n", treap.queryNum(rot, uu)); break;
            case 5:	treap.queryPre(rot, uu); printf("%d\n", treap.val[ans]); break;
            case 6:	treap.queryNxt(rot, uu); printf("%d\n", treap.val[ans]); break;
        }
    }
    return 0;
}

splay做法，参照zyf2000，但是一般我们用splay都是维护区间的

#include <iostream>
#include <cstdio>
using namespace std;
int n, uu, vv, rot=0, sze=0;
struct Splay{
	int s[100005][2], f[100005], siz[100005], cnt[100005], val[100005];
	inline void clr(int x){
		s[x][0] = s[x][1] = f[x] = siz[x] = cnt[x] = val[x] = 0;
	}
	inline void upd(int x){
		siz[x] = siz[s[x][0]] + siz[s[x][1]] + cnt[x];
	}
	inline int gx(int x){
		return s[f[x]][1]==x;
	}
	void rotate(int x){
		int old=f[x], oldf=f[old], w=gx(x);
		s[old][w] = s[x][w^1]; s[x][w^1] = old;
		f[s[old][w]] = old; f[old] = x; f[x] = oldf;
		if(oldf)	s[oldf][s[oldf][1]==old] = x;
		upd(x); upd(old);
	}
	void splay(int x){
		int fa=1;
		while(fa){
			fa = f[x];
			if(!fa)	break;
			if(f[fa])rotate((gx(x)==gx(fa))?fa:x);
			rotate(x);
		}
		rot = x;
	}
	void ins(int x){
		if(!rot){
			rot = ++sze; clr(rot);
			siz[rot] = cnt[rot] = 1; val[rot] = x;
			return ;
		}
		int now=rot, fa=0;
		while(now){
			if(val[now]==x){
				cnt[now]++; upd(now);
				upd(f[now]); splay(now); return ;
			}
			fa = now; now = s[now][val[now]<x];
			if(!now){
				now = ++sze; clr(now); val[now] = x; cnt[now] = siz[now] = 1;
				f[now] = fa; s[fa][val[fa]<x] = now; upd(fa); splay(sze);
				break;
			}
		}
	}
	int getRank(int x){
		int now=rot, ans=0;
		while(now){
			if(x<val[now])	now = s[now][0];
			else{
				ans += siz[s[now][0]];
				if(val[now]==x){
					splay(now);
					return ans+1;
				}
				ans += cnt[now];
				now = s[now][1];
			}
		}
	}
	int getNum(int x){
		int now=rot;
		while(now){
			if(x<=siz[s[now][0]])	now = s[now][0];
			else{
				int temp=siz[s[now][0]]+cnt[now];
				if(x<=temp)	return val[now];
				x -= temp; now = s[now][1];
			}
		}
	}
	int getPre(){
		int now=s[rot][0];
		while(s[now][1])	now = s[now][1];
		return now;
	}
	int getNxt(){
		int now=s[rot][1];
		while(s[now][0])	now = s[now][0];
		return now;
	}
	void del(int x){
		getRank(x);
		if(cnt[rot]>1){
			cnt[rot]--; upd(rot);
			return ;
		}
		if(!s[rot][0] && !s[rot][1]){
			clr(rot); rot = sze = 0;
			return ;
		}
		if(!s[rot][0]){
			int oldr=rot; rot = s[rot][1]; f[rot] = 0; clr(oldr);
			return ;
		}
		if(!s[rot][1]){
			int oldr=rot; rot = s[rot][0]; f[rot] = 0; clr(oldr);
			return ;
		}
		int leftBig=getPre(), oldr=rot;
		splay(leftBig); s[rot][1] = s[oldr][1];
		f[s[rot][1]] = rot; clr(oldr); upd(rot);
	}
}splay;
int main(){
	cin>>n;
	while(n--){
		scanf("%d %d", &uu, &vv);
		switch(uu){
			case 1: splay.ins(vv); break;
			case 2: splay.del(vv); break;
			case 3: printf("%d\n", splay.getRank(vv)); break;
			case 4: printf("%d\n", splay.getNum(vv)); break;
			case 5: splay.ins(vv); printf("%d\n", splay.val[splay.getPre()]); splay.del(vv); break;
			case 6: splay.ins(vv); printf("%d\n", splay.val[splay.getNxt()]); splay.del(vv); break;
		}
	}
	return 0;
}