正题

评测记录:https://www.luogu.org/recordnew/lists?uid=SSL_WYC_zombieeeeee&pid=P3369&status=&sort=0

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题目大意

要求支持查询一个数字的排名，查询该排名的数字，插入数字，删除数字，求前驱后继。

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解题思路

有旋Treap不解释。

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$code$

#include<cstdio>
#include<algorithm>
#define INF 2147483647/3
#define N 100010
using namespace std;
int n,root;
struct Treap_node{int l[N],r[N];int val[N],dat[N];int cnt[N],size[N];int tot;int New(int new_val){val[++tot]=new_val;dat[tot]=rand();cnt[tot]=size[tot]=1;return tot;}void Updata(int p){size[p]=size[l[p]]+size[r[p]]+cnt[p];}void Build(){New(-INF);New(INF);root=1;r[1]=2;Updata(root);}int GetRankByVal(int p,int num){if(p==0) return 0;if(num==val[p]) return size[l[p]]+1;if(num<val[p]) return GetRankByVal(l[p],num);return GetRankByVal(r[p],num)+size[l[p]]+cnt[p];}int GetValByRank(int p,int rank){if (p==0) return INF;if(size[l[p]]>=rank) return GetValByRank(l[p],rank);if(size[l[p]]+cnt[p]>=rank) return val[p];return GetValByRank(r[p],rank-size[l[p]]-cnt[p]);}void zig(int &p){int q=l[p];l[p]=r[q];r[q]=p;p=q;Updata(r[p]);Updata(p);}void zag(int &p){int q=r[p];r[p]=l[q];l[q]=p;p=q;Updata(l[p]);Updata(p);}void Insert(int &p,int num){if(p==0){p=New(num);return;}if(num==val[p]){cnt[p]++;Updata(p);return;}if(num<val[p]){Insert(l[p],num);if(dat[p]<dat[l[p]]) zig(p);}else{Insert(r[p],num);if(dat[p]<dat[r[p]]) zag(p);}Updata(p);}int GetPre(int num){int ans=1;int p=root;while(p){if(num==val[p]){if(l[p]>0){p=l[p];while(r[p]>0) p=r[p];ans=p;}break;}if(val[p]<num&&val[p]>val[ans]) ans=p;p=num<val[p]?l[p]:r[p];}return val[ans];}int GetNext(int num){int ans=2;int p=root;while(p){if(num==val[p]){if(r[p]>0){p=r[p];while(l[p]>0) p=l[p];ans=p;}break;}if(val[p]>num&&val[p]<val[ans]) ans=p;p=num<val[p]?l[p]:r[p];}return val[ans];}void Remove(int &p,int num){if(p==0) return;if(num==val[p]){if(cnt[p]>1){cnt[p]--;Updata(p);return;}if(l[p]||r[p]){if(r[p]==0||dat[l[p]]>dat[r[p]])zig(p),Remove(r[p],num);elsezag(p),Remove(l[p],num);Updata(p);}else p=0;return;}num<val[p]?Remove(l[p],num):Remove(r[p],num);Updata(p);}
}a;
int main()
{a.Build();scanf("%d",&n);while(n--){int opt,x;scanf("%d%d",&opt,&x);switch(opt){case 1:a.Insert(root,x);break;case 2:a.Remove(root,x);break;case 3:printf("%d\n",a.GetRankByVal(root,x)-1);break;case 4:printf("%d\n",a.GetValByRank(root,x+1));break;case 5:printf("%d\n",a.GetPre(x));break;case 6:printf("%d\n",a.GetNext(x));break;}}
}