HDU 1251 统计难题

#include<cstdio>
#include<cstring>
using namespace std;
#define N 500000

struct node{
    bool have;
    int son[26];
    int cnt;
    int acnt;
    node(){
        have=0;
        cnt=0;
        acnt=0;
        memset(son,0,sizeof(son));
    }
}trie[N]; 
int num;
void insert(char *s)
{
    int pos=0,len=strlen(s);
    int fa=0;
    for(int i=0;i<len;++i)
    {
        pos=s[i]-‘a‘;
        if(!trie[fa].son[pos]){
            trie[fa].son[pos]=++num;
        }
        fa=trie[fa].son[pos];
        trie[fa].cnt++;
    }
    trie[fa].have=1;
    trie[fa].acnt++;
}
int find(char *s)
{
    int len=strlen (s);
    int pos,fa=0;
    for(int i=0;i<len;++i)
    {
        pos=s[i]-‘a‘;
        if(!trie[fa].son[pos]){
            return 0;
        }
        fa = trie[fa].son[pos];
    }
    return trie[fa].cnt;
}
int main()
{
    char word[20];
    while(gets(word))
    {
        int len=strlen(word);
        if(len==0)break;
        else insert(word);
    }
    while(gets(word))
    {
        printf("%d\n",find(word));
    }
    return 0;
}