hdu1251统计难题

#include<iostream>
#include<cstring>
#include<cstdio>
#include<cmath>

using namespace std;

struct node
{
    node* next[26];
    int num;
    node()
    {
        for(int i = 0;i<26;i++)
            next[i] = NULL;
        num = 0;
    }
};
node* root = new node();
char s[15];
void insert()
{
    int i,l = strlen(s);
    node* k = root;
    for(i = 0;i<l;i++)
    {
        int id = s[i]-‘a‘;
        if(k->next[id] == NULL)
        {
            node* t = new node();
            k->next[id] = t;

        }
        k = k->next[id];
        k->num++;
    }
}
int find()
{
    int i,l = strlen(s);
    node* k = root;
    for(i = 0;i<l;i++)
    {
        int id = s[i]-‘a‘;
        if(k->next[id] == NULL) return 0;
        else k = k->next[id];
    }
    return k->num;
}

int main()
{
    bool b = 0;
    while(gets(s))
    {
        if(s[0] == ‘\0‘) break;
        insert();
    }
    while(scanf("%s",s)!=EOF)
        printf("%d\n",find());
    return 0;
}