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class="java" name="code">package edu.xmu.guava.jcip; import java.util.Map; public interface Traversable { public void addWord(String word, int index); public Traversable getNext(Character c); public Map<Character, ? extends Traversable> getChildren(); }
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package edu.xmu.guava.jcip; import java.util.Map; import java.util.Scanner; import java.util.Stack; import java.util.TreeMap; public class Dictionary { public static void main(String[] args) { Traversable rootNode = new VirtualHeaderNode(); rootNode.addWord("Hello", 0); rootNode.addWord("Welcome", 0); rootNode.addWord("Yang", 0); rootNode.addWord("Yes", 0); rootNode.addWord("Good", 0); rootNode.addWord("God", 0); rootNode.addWord("Yeah", 0); rootNode.addWord("Yep", 0); System.out.println(rootNode.getChildren().keySet()); Stack<Traversable> wordStack = new Stack<Traversable>(); Scanner scanner = new Scanner(System.in); String str = scanner.next(); Traversable currentNode = rootNode; wordStack.push(currentNode); while (true) { if ("POP".equals(str)) { if (!(wordStack.peek() instanceof VirtualHeaderNode)) { wordStack.pop(); currentNode = wordStack.peek(); } } else if ("EXIT".equals(str)) { scanner.close(); break; } else { char alpha = str.charAt(0); if (currentNode.getChildren().containsKey(alpha)) { currentNode = currentNode.getChildren().get(alpha); wordStack.push(currentNode); } } Map<Character, ? extends Traversable> next = currentNode .getChildren(); System.out.println(next.keySet()); str = scanner.next(); }; } public static class VirtualHeaderNode implements Traversable { private Map<Character, Traversable> children = new TreeMap<Character, Traversable>(); @Override public void addWord(String word, int index) { char c = word.charAt(0); Traversable headerNode; if (children.containsKey(c)) { headerNode = children.get(c); } else { headerNode = new AlphabetNode(); children.put(c, headerNode); } headerNode.addWord(word, index); } @Override public Traversable getNext(Character c) { return children.get(c); } @Override public Map<Character, Traversable> getChildren() { return children; } } public static class AlphabetNode implements Traversable { private AlphabetNode parent; private Map<Character, AlphabetNode> children = new TreeMap<Character, AlphabetNode>(); private char value; public void addWord(String word, int i) { this.value = word.charAt(i); if (i >= (word.length() - 1)) { return; } char childValue = word.charAt(i + 1); AlphabetNode childNode; if (children.containsKey(childValue)) { childNode = children.get(childValue); } else { childNode = new AlphabetNode(); childNode.setParent(this); childNode.setValue(childValue); children.put(childValue, childNode); } childNode.addWord(word, i + 1); } public AlphabetNode getParent() { return parent; } public void setParent(AlphabetNode parent) { this.parent = parent; } public Map<Character, AlphabetNode> getChildren() { return children; } public void setChildren(Map<Character, AlphabetNode> children) { this.children = children; } public char getValue() { return value; } public void setValue(char value) { this.value = value; } @Override public String toString() { return "AlphabetNode [value=" + value + "]"; } @Override public AlphabetNode getNext(Character c) { return children.get(c); } } }
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