C++ 代码

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

struct Node{
    int cnt = 0;
    Node* child[26];
};

Node* head = new Node();

void insert(string s){
    Node *p = head;
    for(char c:s){
        int u = c - 'a';
        if(p->child[u] == nullptr){
            p->child[u] = new Node();
        }
        p = p->child[u];
    }

    p->cnt += 1;
    return;
}


int find(string s){
    Node *p = head;
    for(char c:s){
        int u = c - 'a';
        if(p->child[u] == nullptr) return 0;
        p = p->child[u];
    }

    return p->cnt;
}

int n;
int main(){
    cin>>n;
    while(n--){
        char op;string s;
        cin>>op>>s;
        if(op == 'I'){
            insert(s);
        }else{
            cout<<find(s)<<endl;
        }
    }
}