HDU-5687 Problem C （字典树）插入，查找，删除

#include <iostream>
#include <algorithm>
#include <cstring>
#include <string>
#include <vector>

using namespace std;
typedef long long ll;

const int maxn = 1300005;
int pos = 1;

int trie[maxn][26];
int num[maxn];

void insert(string str)
{
    int p = 0;
    for (int i = 0; str[i]; i++)
    {
        int n = str[i] - 'a';
        if (!trie[p][n])
        {
            trie[p][n] = pos++;
        }
        p = trie[p][n];
        num[p]++;
    }
}

int Find(string str)
{
    int p = 0;
    for (int i = 0; str[i]; i++)
    {    
        int n = str[i] - 'a';
        if (!trie[p][n])
            return 0;
        p = trie[p][n];
    }
    return num[p];
}

void Delete(string str)
{
    int p = 0;
    for (int i = 0; str[i]; i++)
    {
        int n = str[i] - 'a';
        if (!trie[p][n]) return;
        p = trie[p][n];
    }
    int cnt = num[p];
    // 先跑一遍，看有没有这个string。
    p = 0;
    for (int i = 0; str[i]; i++)
    {
        int n = str[i] - 'a';
        p = trie[p][n];
        num[p] -= cnt;
    }
    for (int i = 0; i < 26; i++)
    {
        trie[p][i] = 0;
    }
}

int main()
{
    int t;
    cin >> t;
    string c, s;
    while (t--)
    {
        cin >> c >> s;
        if (c == "insert") insert(s);
        else if (c == "search")
        {
            if (Find(s)) cout << "Yes" << endl;
            else cout << "No" << endl;
        }
        else Delete(s);
    }
    return 0;
}