http://acm.hdu.edu.cn/showproblem.php?pid=1251
#include<iostream>
using namespace std;
struct dictree
{
    struct dictree *child[26];
    int num;
};
int main()
{
    int i;
    char word[11];
    struct dictree root;// = new dictree;
    for(i=0;i<26;i++)
        root.child[i] = NULL;
    root.num = 0;
    while(cin.getline(word,11),word[0])//輸入方法很niu
    {
        struct dictree *now = &root;
        char *tmp = word;
        while(*tmp)
        {
            if(now->child[*tmp-'a']==NULL)
            {
                now->child[*tmp-'a']=new dictree;
                now=now->child[*tmp-'a'];
                for(i=0;i<26;i++)
                    now->child[i] = NULL;
                now->num = 1;
            }
            else
            {
                now=now->child[*tmp-'a'];
                now->num ++;
            }
            tmp++;
        }
    }    
    while(cin.getline(word,11),cin && word[0])
    {
        int mins=100000;
        struct dictree *now = &root;
        char *tmp = word;
        while(*tmp)
        {
            now=now->child[*tmp-'a'];
            if(!now)
            {
                mins = 0;
                break;
            }
            if(now->num < mins)
                mins = now->num;
            tmp++;
        }
        cout<<mins<<endl;
    }
    return 0;
}