关于leetcode:实现-Trie-前缀树

class Trie {    class TrieNode {        private boolean isEnd;        private TrieNode[] links;        TrieNode() {            links = new TrieNode[26];        }        public boolean containsKey(char ch) {            return links[ch-'a'] != null;        }        public TrieNode get(char ch) {            return links[ch-'a'];        }        public void put(char ch, TrieNode node) {            links[ch-'a'] = node;        }        public void setEnd() {            isEnd = true;        }        public boolean isEnd() {            return isEnd;        }    }    private TrieNode root;    /** Initialize your data structure here. */    public Trie() {        root = new TrieNode();    }        /** Inserts a word into the trie. */    public void insert(String word) {        TrieNode node = root;        for(char ch : word.toCharArray()) {            if(!node.containsKey(ch)) {                node.put(ch, new TrieNode());            }            node = node.get(ch);        }        node.setEnd();    }        /** Returns if the word is in the trie. */    public boolean search(String word) {        TrieNode node = root;        for(char ch : word.toCharArray()) {            if(!node.containsKey(ch)) {                return false;            }            node = node.get(ch);        }        return node.isEnd();    }        /** Returns if there is any word in the trie that starts with the given prefix. */    public boolean startsWith(String prefix) {        TrieNode node = root;        for(char ch : prefix.toCharArray()) {            if(!node.containsKey(ch)) {                return false;            }            node = node.get(ch);        }        return true;    }}/** * Your Trie object will be instantiated and called as such: * Trie obj = new Trie(); * obj.insert(word); * boolean param_2 = obj.search(word); * boolean param_3 = obj.startsWith(prefix); */