名次树treap代码

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<cstring>
#include<vector>
using namespace std;
typedef long long LL;
const int MAXN=200000+10; 
const int INF=0x7fffffff;
struct NODE{
    NODE *ch[2];
    int r,v;
    int s;
    NODE(int v=0):v(v){r=rand();s=1;ch[1]=ch[0]=NULL;}
    bool operator < (const NODE &rhs) const {
        return r<rhs.r;
    }
    int cmp(int x){
        if(x == v) return -1;
        return x < v ? 0 : 1;
    }
    void mt(){
        s=1;
        if(ch[0] != NULL) s+=ch[0]->s;
        if(ch[1] != NULL) s+=ch[1]->s;
    }
};
void rotate(NODE *&o,int d){
    NODE *k=o->ch[d^1];o->ch[d^1]=k->ch[d];k->ch[d]=o;
    o->mt();k->mt();o=k;
}
void insert(NODE *&o,int x){
    if(o == NULL) o=new NODE(x);
    else {
        int d=o->v > x ? 0 : 1;
        insert(o->ch[d],x);
        if(o->ch[d]->r > o->r) rotate(o,d^1);
    }
    o->mt();
}

void remove(NODE *&o,int x){
    int d=o->cmp(x);
    int ret=0;
    if(d == -1){
        NODE *u=o;
        if(o->ch[1] != NULL && o->ch[0] != NULL){
            int d2=(o->ch[0]->r > o->ch[1]->r ? 1 : 0);
            rotate(o,d2);remove(o->ch[d2],x);
        }
        else {
            if(o->ch[0] == NULL) o=o->ch[1];
            else o=o->ch[0];
            delete u;
        }
    }
    else {
        remove(o->ch[d],x);
    }
    if(o != NULL) o->mt();
}

NODE *find(NODE *o,int x){
    if(o == NULL) return NULL;
    if(x == o->v) return o;
    return x < o->v ? find(o->ch[0],x) : find(o->ch[1],x); 
}

int kth(NODE *o,int k){
    if(k <= 0 || o == NULL || k > o->s) return 0;
    int s=(o->ch[0] == NULL ? 0 : o->ch[0]->s);
    if(k == s+1) return o->v;
    else if(k <= s) return kth(o->ch[0],k);
    else return kth(o->ch[1],k-s-1);
}

int rank(NODE *o,int x){
    if(o == NULL) return 1;
    if(x <= o->v) return rank(o->ch[0],x);
    return rank(o->ch[1],x)+(o->ch[0] == NULL ? 0:o->ch[0]->s)+1;
}

int prec(NODE *o,int t){//小于t的最大数 
    int ans=-INF;
    if(t > o->v){
        if(o->ch[1] != NULL) ans=prec(o->ch[1],t);
        return max(ans,o->v);
    }
    else if(o->ch[0] != NULL) ans=prec(o->ch[0],t);
    return ans;
}

int succ(NODE *o,int t){//大于t的最小数 
    int ans=INF;
     if(t < o->v){
         if(o->ch[0] != NULL) ans=succ(o->ch[0],t);
         return min(ans,o->v);
     }
     else if(o->ch[1] != NULL) ans=succ(o->ch[1],t);
     return ans;
}

#define submit
int main(){
#ifdef submit
    freopen("phs.in","r",stdin);
    freopen("phs.out","w",stdout);
#endif
#ifdef submi
    freopen("in.txt","r",stdin);
#endif
    int m,c,v;
    NODE *root=new NODE(INF);
    root->r=0x7fffffff;
    insert(root,INF);
    scanf("%d",&m);
    while(m--){
        scanf("%d %d",&c,&v);
        if(c == 1) insert(root,v);
        else if(c == 2){
            NODE *o=find(root,v);
            if(o != NULL) remove(root,v);
        }
        else if(c == 4) printf("%d
",kth(root,v));
        else if(c == 3) printf("%d
",rank(root,v));
        else if(c == 5) printf("%d
",prec(root,v));
        else if(c == 6) printf("%d
",succ(root,v));
    }
    return(0);
}