Tire 模板 高效存储和查找字符串

ACWING 835. Trie字符串统计

#include <bits/stdc++.h>
using namespace std;

const int N  = 100005;  
int idx;    //每个节点的唯一标识
int son[N][26], cnt[N];    
char s1[N], s2[N];    

void insert(char s[]) {
    int p = 0;
    for (int i = 0; s[i]; ++i) {
        int u = s[i] - 'a';
        if (!son[p][u]) {
            //创建新节点
            son[p][u] = ++idx;
        }
        p = son[p][u];
    }
    ++cnt[p];   //son[p][*]一定为0, 代表单词结尾
}

int query(char s[]) {
    int p = 0;
    for (int i = 0; s[i]; ++i) {
        int u = s[i] - 'a';
        if (son[p][u] == 0) {
            //无法找到下一个字符，代表该字符串没有出现过
            return 0;
        }
        p = son[p][u];
    }

    return cnt[p];
}

int main() {
#ifndef ONLINE_JUDGE
    freopen("D:/VS CODE/C++/in.txt", "r", stdin);
    freopen("D:/VS CODE/C++/out.txt", "w", stdout);
#endif
    int n;
    cin >> n;

    while (n--) {
        scanf("%s %s", &s1, &s2);
        if (s1[0] == 'I') {
            insert(s2);
        }
        else {
            cout << query(s2) << endl;
        }
    }

    fclose(stdin);
    fclose(stdout);
    return 0;
}