统计难题

Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 131070/65535 K (Java/Others)
Total Submission(s): 69481    Accepted Submission(s): 24045


Problem Description
Ignatius最近遇到一个难题,老师交给他很多单词(只有小写字母组成,不会有重复的单词出现),现在老师要他统计出以某个字符串为前缀的单词数量(单词本身也是自己的前缀).
 

Input
输入数据的第一部分是一张单词表,每行一个单词,单词的长度不超过10,它们代表的是老师交给Ignatius统计的单词,一个空行代表单词表的结束.第二部分是一连串的提问,每行一个提问,每个提问都是一个字符串.

注意:本题只有一组测试数据,处理到文件结束.
 

Output
对于每个提问,给出以该字符串为前缀的单词的数量.
 

Sample Input
banana
band
bee
absolute
acm


ba
b
band
abc
 

Sample Output
2
3
1
0
 

Author
Ignatius.L
 

Recommend
Ignatius.L
 

<center style="font&#45;size&#58;15px&#59;font&#45;family&#58;Arial&#59;font&#45;weight&#58;bold&#59;color&#58;&#35;1A5CC8">Statistic | Submit | Discuss | Note
import java.util.Scanner;
public class Main {
    static int Size = 26;
    static TrieNode root;
    static class TrieNode {
        int num;
        TrieNode son[];
        boolean isEnd;
        char val;
        TrieNode() {
            num = 1;
            son = new TrieNode[Size];
            isEnd = false;
        }
    }
    static void add_str(String str) {
        if (str == null || str.length() == 0) {
            return;
        }
        TrieNode node = root;
        char ch[] = str.toCharArray();
        int length = ch.length, pos;
        for (int i = 0; i < length; i++) {
            pos = ch[i] - 'a';
            if (node.son[pos] == null) {
                node.son[pos] = new TrieNode();
                node.son[pos].val = ch[i];
            } else {
                node.son[pos].num++;
            }
            node = node.son[pos];
        }
        node.isEnd = true;
    }
    static int ans(String str) {
        if (str == null || str.length() == 0) {
            return -1;
        }
        TrieNode node = root;
        char ch[] = str.toCharArray();
        int length = ch.length, pos;
        for (int i = 0; i < length; i++) {
            pos = ch[i] - 'a';
            if (node.son[pos] == null) {
                return 0;
            } else {
                node = node.son[pos];
            }
        }
        return node.num;
    }
    public static void main(String[] args) {
        /*BufferedInputStream in = new BufferedInputStream(new FileInputStream("C:\\Users\\date.txt"));
        System.setIn(in);*/
        Scanner sc = new Scanner(System.in);
        while (sc.hasNext()) {
            root = new TrieNode();
            String str;
            while (!(str = sc.nextLine()).equals("")) {
                add_str(str);
            }
            while (sc.hasNext()) {
                str = sc.next();
                System.out.println(ans(str));
            }
        }
    }
}
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