POJ2001字典树

给出n个单词，求出每个单词的非公共前缀，如果没有，则输出自己。

import java.io.BufferedReader;import java.io.InputStream;import java.io.InputStreamReader;import java.io.PrintWriter;import java.io.UnsupportedEncodingException;import java.math.BigInteger;import java.util.ArrayList;import java.util.List;import java.util.StringTokenizer;public class Main {public static void main(String[] args)  {new Task().solve();}}class Task {class Node {int cnt ;Node[] next ;Node(){cnt = 0 ;next = new Node[26] ;}}void add(Node root , String word){Node now = root ;for(char c : word.toCharArray()){int idx = c - 'a' ;if(now.next[idx] == null)now.next[idx] = new Node() ;now = now.next[idx] ;now.cnt++ ;}}String query(Node root , String word){Node now = root ;for(int i = 0 ; i < word.length() ; i++){int idx = word.charAt(i) - 'a' ;now = now.next[idx] ;if(now.cnt == 1) return word.substring(0, i+1) ;}return word ;}void solve() {Node root = new Node() ;List<String> words = new ArrayList<String>() ;while(in.hasNext()){String word = in.next() ;words.add(word) ;add(root, word) ;}for(String word : words) out.println(word + " " + query(root, word)) ;out.flush();}InputReader in = new InputReader(System.in);PrintWriter out = new PrintWriter(System.out);}class InputReader {public BufferedReader reader;public StringTokenizer tokenizer;public InputReader(InputStream stream) {reader = new BufferedReader(new InputStreamReader(stream), 32768);tokenizer = new StringTokenizer("");}private void eat(String s) {tokenizer = new StringTokenizer(s);}public String nextLine() {try {return reader.readLine();} catch (Exception e) {return null;}}public boolean hasNext() {while (!tokenizer.hasMoreTokens()) {String s = nextLine();if (s == null)return false;eat(s);}return true;}public String next() {hasNext();return tokenizer.nextToken();}public int nextInt() {return Integer.parseInt(next());}public long nextLong() {return Long.parseLong(next());}public double nextDouble() {return Double.parseDouble(next());}public BigInteger nextBigInteger() {return new BigInteger(next());}}