前缀树(字典树)
作者:互联网
力扣208.实现一棵前缀树
class Trie { // 前缀树的节点 class TrieNode { boolean isWord = false; // 表示该节点是否是单词的最后一个字符 TrieNode[] children; public TrieNode() { children = new TrieNode[26]; } } TrieNode root; // 根节点,作为哨兵 /** Initialize your data structure here. */ public Trie() { root = new TrieNode(); } /** Inserts a word into the trie. */ public void insert(String word) { TrieNode cur = root; for (int i = 0; i < word.length(); i++) { int index = word.charAt(i) - 'a'; if (cur.children[index] == null) { // 表示字符还未插入 cur.children[index] = new TrieNode(); } cur = cur.children[index]; } cur.isWord = true; } /** Returns if the word is in the trie. */ public boolean search(String word) { TrieNode cur = root; for (int i = 0; i < word.length(); i++) { int index = word.charAt(i) - 'a'; if (cur.children[index] == null) { return false; } cur = cur.children[index]; } if (!cur.isWord) return false; // 走到该节点,还要继续判断以该节点是不是单词的结尾 return true; } /** Returns if there is any word in the trie that starts with the given prefix. */ public boolean startsWith(String prefix) { TrieNode cur = root; for (int i = 0; i < prefix.length(); i++) { int index = prefix.charAt(i) - 'a'; if (cur.children[index] == null) { return false; } cur = cur.children[index]; } 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); */
标签:index,word,cur,TrieNode,int,字典,children,前缀 来源: https://www.cnblogs.com/xiazhenbin/p/14993555.html