模板汇总——treap

1. 旋转treap。

思想：一颗权值BST + 一颗 随机数 最小堆。

BZOJ - 3224

代码：

#include<bits/stdc++.h>
using namespace std;
#define Fopen freopen("_in.txt","r",stdin); freopen("_out.txt","w",stdout);
#define LL long long
#define ULL unsigned LL
#define fi first
#define se second
#define pb push_back
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
#define lch(x) tr[x].son[0]
#define rch(x) tr[x].son[1]
#define max3(a,b,c) max(a,max(b,c))
#define min3(a,b,c) min(a,min(b,c))
typedef pair<int,int> pll;
#define inf 300000030
const int _inf = 0xc0c0c0c0;
const LL INF = 0x3f3f3f3f3f3f3f3f;
const LL _INF = 0xc0c0c0c0c0c0c0c0;
const LL mod =  (int)1e9+7;
const int N = 1e5 + 100;
struct Treap{
    int L[N], R[N], sz[N], v[N], rnd[N], ct[N], tot, root;
    void init(){
        tot = root = 0;
    }
    inline int rand(){
        static int seed = 12345;
        return seed = (int)seed * 482711LL % 2147483647;
    }
    void Updata(int p){
        sz[p] = ct[p] + sz[L[p]] + sz[R[p]];
    }
    void turnL(int &k){
        int t = R[k];
        R[k] = L[t];
        L[t] = k;
        sz[t] = sz[k];
        Updata(k);
        k = t;
    }
    void turnR(int &k){
        int t = L[k];
        L[k] = R[t];
        R[t] = k;
        sz[t] = sz[k];
        Updata(k);
        k = t;
    }
    void Insert(int &p, int x){
        if(!p){
            p = ++tot;
            sz[p] = ct[p] = 1;
            v[p] = x; rnd[p] = rand();
            return ;
        }
        sz[p]++;
        if(v[p] == x) ct[p]++;
        else if(x > v[p]){
            Insert(R[p], x);
            if(rnd[R[p]] < rnd[p]) turnL(p);
        }
        else {
            Insert(L[p], x);
            if(rnd[L[p]] < rnd[p]) turnR(p);
        }
    }
    void Delete(int &p, int x){
        if(!p) return ;
        if(v[p] == x){
            if(ct[p] > 1) ct[p]--, sz[p]--;
            else {
                if(L[p] == 0 || R[p] == 0) p = L[p] + R[p];
                else if(rnd[L[p]] < rnd[R[p]]) turnR(p), Delete(p, x);
                else turnL(p), Delete(p, x);
            }
        }
        else if(x > v[p]) sz[p]--, Delete(R[p], x);
        else sz[p]--, Delete(L[p], x);
    }
    int Query_Rank_of_x(int p, int x){
        if(!p) return 0;
        if(v[p] == x) return sz[L[p]]+1;
        if(v[p] > x) return Query_Rank_of_x(L[p], x);
        return ct[p] + sz[L[p]] + Query_Rank_of_x(R[p], x);
    }
    int Query_kth(int p, int k){
        if(!p) return -1;
        if(sz[L[p]] >= k) return Query_kth(L[p], k);
        k -= sz[L[p]];
        if(k <= ct[p]) return v[p];
        k -= ct[p];
        return Query_kth(R[p], k);
    }
    int FindFront(int p, int x){
        if(!p) return -inf;
        if(v[p] < x) return max(v[p], FindFront(R[p], x));
        return FindFront(L[p], x);
    }
    int FindNext(int p, int x){
        if(!p) return inf;
        if(v[p] <= x) return FindNext(R[p], x);
        return min(v[p], FindNext(L[p], x));
    }
}treap;
int main(){
    int T;
    int op, x;
    scanf("%d", &T);
    treap.init();
    while(T--){
        scanf("%d%d", &op, &x);
        if(op == 1) treap.Insert(treap.root, x);
        else if(op == 2) treap.Delete(treap.root, x);
        else if(op == 3) printf("%d\n", treap.Query_Rank_of_x(treap.root, x));
        else if(op == 4) printf("%d\n", treap.Query_kth(treap.root, x));
        else if(op == 5) printf("%d\n", treap.FindFront(treap.root, x));
        else if(op == 6) printf("%d\n", treap.FindNext(treap.root, x));
    }
    return 0;
}

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