字典树

敲出来字典树模板，用的双指针建的

#include <iostream>
#include <string>
#include <regex>
using namespace std;
const int N = 26;
struct trieNode{
    char c;
    trieNode** son;
    int cnt = 0;
    trieNode (char C){
        cnt = 0;
        c=C;
        son = new trieNode *[N];
        for(int i = 0;i < N;i++){
            son[i] = nullptr;
        }
    };
};
trieNode *root;
void insert(string s)
{
    trieNode *p;
    p = root;
    for(int i = 0;i < s.size();i++){
        int x = s[i] - 'a';
        if(!p->son[x])   p->son[x] = new trieNode(s[i]);
        p = p->son[x];
    }
    p->cnt++;
}
int query(string s)
{
    trieNode *p;
    p = root;
    for(int i=0;i < s.size();i++){
        if(p->son[s[i]-'a']== nullptr)  return 0;
        p = p->son[s[i]-'a'];
    }
    return p->cnt;
}
int main()
{
    root = new trieNode(' ');
    string s;
    for(int i=0;i<5;i++){
        cin>>s;
        insert(s);
    }
    for(int i=0;i<3;i++){
        cin>>s;
        cout<<query(s);
    }
    return 0;
}