点击打开题目链接

大致题意：给定一系列单词，为每个单词寻找最短前缀使其能被唯一标识，与其他单词都区分开来

网上百度出的几道Trie树的题目发现用容器，比如HashMap等就可以做，但是这道似乎就不行了，相当来说

应该是Trie树的典型应用题。思路比较简单，就是Trie树建立，结点统计被几个单词占用了，然后再对每个单词

遍历一遍Trie树找到第一个结点只被该单词占用的(即该结点上记录的cnt值为1)。如果遍历完了都没有，说明

该单词最短前缀只能是该单词自身了。其实理解了Trie树这道题还是好做的。

代码如下：

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {

    /**
     * @param args
     */
    static BufferedReader reader;
    static String str;
    static char ch[][];
    static int cnt, num;
    static int arr[][];
    static int word[], nums[], pre[], ans[];

    private static void deal() {
        int number, totalnum;
        totalnum = 0;
        word = new int[21 * cnt + 1];
        nums = new int[21 * cnt + 1];
        ans = new int[cnt + 1];
        for (int i = 1; i <= cnt; i++) {
            number = 0;
            for (int j = 0; j < ch[i].length; j++)
                if (arr[number][ch[i][j] - 'a'] == 0) {
                    totalnum++;
                    arr[number][ch[i][j] - 'a'] = totalnum;
                    nums[totalnum]++;
                    number = totalnum;
                } else {
                    number = arr[number][ch[i][j] - 'a'];
                    nums[number]++;
                }
            word[number] = i;
        }
        for (int i = 1; i <= cnt; i++) {
            number = 0;
            totalnum = 0;
            for (int j = 0; j < ch[i].length; j++) {
                number = arr[number][ch[i][j] - 'a'];
                totalnum++;
                if (nums[number] == 1)
                    break;
            }
            ans[i] = totalnum;
        }
        for (int i = 1; i <= cnt; i++) {
            for (int j = 0; j < ch[i].length; j++)
                System.out.print(ch[i][j]);
            System.out.print(" ");
            for (int j = 0; j < ans[i]; j++)
                System.out.print(ch[i][j]);
            System.out.println();
        }
    }

    public static void main(String[] args) throws IOException {
        // TODO Auto-generated method stub
        reader = new BufferedReader(new InputStreamReader(System.in));
        str = reader.readLine();
        ch = new char[1001][];
        cnt = 0;
        while (str != null) {
            cnt++;
            ch[cnt] = str.toCharArray();
            str = reader.readLine();
        }
        arr = new int[21 * cnt + 1][27];
        deal();
    }

}