跳表模板

class Skiplist {
public: 
static constexpr int MAX_LEVEL = 16;
    static constexpr double P = 0.6;
    //随机数产生相关,#include<random>，详见cppreference
    std::random_device rd;
    std::mt19937 gen;
    std::uniform_real_distribution<> dis;
    struct node
    {
        int data;
        node *next[MAX_LEVEL+1];
        node()
        {
            for(int i=1;i<=MAX_LEVEL;i++)
                next[i] = NULL;
        }
    };
    node *head;
    Skiplist() {
        head = new node;
        gen = std::mt19937(rd());
        dis = std::uniform_real_distribution<> (0,1);
    }
    int randomLevel()
    {
        int ret = 1;
        while(ret<MAX_LEVEL && dis(gen)<P)
            ret++;
        return ret;
    }
    bool search(int target) {
        node *now = head;
        for(int i=MAX_LEVEL;i>=1;i--)
            while(now->next[i] != NULL && now->next[i]->data<target) now = now->next[i];
        if(now->next[1] == NULL) return false;
        if(now->next[1]->data != target) return false;
        return true;

    }
    
    void add(int num) {
        node *tmp = new node;
        tmp->data = num;
        node *pre[MAX_LEVEL+1];//前驱
        node *now = head;
        int level = randomLevel();
        for(int i=MAX_LEVEL;i>=1;i--)
        {
            while(now->next[i] != NULL && now->next[i]->data<num) now = now->next[i];
            pre[i] = now;
        }
        for(int i=level;i>=1;i--)
        {
            tmp->next[i] = pre[i]->next[i];
            pre[i]->next[i] = tmp;
        }
    }
    
    bool erase(int num) {
       node *pre[MAX_LEVEL+1];
        node *now = head;
        for(int i=MAX_LEVEL;i>=1;i--)
        {
            while(now->next[i] != NULL && now->next[i]->data<num) now = now->next[i];
            pre[i] = now;
        }
        if(now->next[1] == NULL) return false;
        if(now->next[1]->data !=num) return false;
        for(int i=MAX_LEVEL;i>=1;i--)
        {
            if(pre[i]->next[i]!=NULL)pre[i]->next[i] = pre[i]->next[i]->next[i];
            else pre[i]->next[i]=NULL;
        }
         
        return true;
    }
};

参考文献