trie树(字典树)java实现

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public class Trie{    private Node root;     public Trie(){        root = new Node(' ');     }     public void insert(String word){    if(search(word) == true) return;            Node current = root;         for(int i = 0; i < word.length(); i++){            Node child = current.subNode(word.charAt(i));            if(child != null){                 current = child;            } else {                 current.childList.add(new Node(word.charAt(i)));                 current = current.subNode(word.charAt(i));            }            current.count++;        }         current.isEnd = true;    }

/**     *怎么判断单词是否存在？     *被判断的单词的字母与根节点下的子节点的字母进行比较，直到匹配到两者最后一个字母相同，并且最后一个节点的isEnd标记为true     */    public boolean search(String word){    Node current = root;            for(int i = 0; i < word.length(); i++){                if(current.subNode(word.charAt(i)) == null)                return false;            else                current = current.subNode(word.charAt(i));        }        if (current.isEnd == true) return true;        else return false;    }        public void deleteWord(String word){if(search(word) == false) return;Node current = root;for(char c : word.toCharArray()) { Node child = current.subNode(c);if(child.count == 1) {current.childList.remove(child);return;} else {child.count--;current = child;}}current.isEnd = false;}

public static void main(String[] args) {Trie trie = new Trie();//trie.insert("ball");trie.insert("balls");trie.deleteWord("balls");trie.insert("sense");// testing deletionSystem.out.println(trie.search("balls"));System.out.println(trie.search("ba"));trie.deleteWord("balls");System.out.println(trie.search("balls"));System.out.println(trie.search("ball"));}}

class Node {    char content; // 节点包含的内容    boolean isEnd; // 是否在该节点行成过一个单词    int count;  // 统计该节点的字符被几个单词共享    LinkedList<Node> childList; // 子节点的集合      //初始化    public Node(char c){        childList = new LinkedList<Node>();        isEnd = false;        content = c;        count = 0;    }      //查找子节点中是否有内容为x的子节点，有则返回该子节点，否则返回空    public Node subNode(char c){        if(childList != null){        for(Node eachChild : childList){            if(eachChild.content == c){                 return eachChild;            }        }        }        return null;   }}

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