字典树 - 神奇的字典

#include<cstdio>
#include<algorithm>
#include<cstring>
#include<string>
#include<queue>
#include<cstdlib>
using namespace std;

struct Trie
{
    int v;
    Trie *next[26];
};

int rec;//用来记录每一次查询存在且以此为前缀的单词的个数
Trie root, *trie, *newtrie;

void Insert(char str[])
{
    int len = strlen(str);
    trie = &root;
    for (int i = 0; i < len; i++)
    {
        int id = str[i] - ‘a‘;
        if (trie -> next[id] == NULL)
        {
            newtrie = (Trie*)malloc(sizeof(Trie));
            for (int i = 0; i < 26; i++) newtrie -> next[i] = NULL;
            trie -> next[id] = newtrie;
            trie -> next[id] -> v = 1;
            trie = trie -> next[id];
        }
        else
        {
            trie -> next[id] -> v ++;
            trie = trie -> next[id];
        }
    }
}

bool Search(char str[])
{
    rec = 0;
    int len = strlen(str);
    trie = &root;
    for (int i = 0; i < len; i++)
    {
        int id = str[i] - ‘a‘;
        if (trie -> next[id] == NULL) return false;
        else trie = trie -> next[id];
    }
    rec = trie -> v;
    return true;
}

void DeleteAll(Trie *t)
{
    for (int i = 0; i < 26; i++)
    {

        if (t -> next[i] != NULL)
        {
            Trie *t1 = t -> next[i];
            DeleteAll(t1);
        }
    }
    free(t);
}

void Delete(char str[])
{
    if (!Search(str)) return ;
    int len = strlen(str);
    trie = &root;
    int sign;
    for (int i = 0; i < len; i++)
    {
        int id = str[i] - ‘a‘;
        trie -> next[id] -> v = trie -> next[id] -> v - rec;//这些地方一定要理清呀，以后抽点时间回来看看
        if (trie -> next[id] -> v == 0)
        {
            newtrie = trie;
            sign = id;
            trie = trie -> next[id];
            break;
        }
        newtrie = trie;
        sign = id;
        trie = trie -> next[id];
    }
    newtrie -> next[sign] = NULL;
    DeleteAll(trie);
}




int main()
{
    //freopen("input.txt", "r", stdin);
    int opera;
    while (scanf("%d", &opera) != EOF)
    {
        while (opera--)
        {
            char op[35], word[35];
            scanf("%s %s", op, word);
            bool yes = false;
            switch (op[0])
            {
            case ‘i‘:
                Insert(word);
                break;
            case ‘s‘:
                yes = Search(word);
                if (yes) printf("Yes\n");
                else printf("No\n");
                break;
            default:
                Delete(word);
                break;
            }
        }
    }
    return 0;
}