leetcode题解（六十）：208. Implement Trie (Prefix Tree)

最新推荐文章于 2022-10-30 07:37:02 发布

原创最新推荐文章于 2022-10-30 07:37:02 发布 · 112 阅读

0 ·

CC 4.0 BY-SA版权

文章标签：

#leetcode

leetcode 专栏收录该内容

73 篇文章

订阅专栏

博客给出了Trie数据结构的操作示例，包括插入字符串、搜索字符串以及判断是否以某字符串开头等操作，并展示了相应操作的返回结果，如插入'apple'后搜索'apple'返回true等。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

例子：
Example:

Trie trie = new Trie();

trie.insert(“apple”);
trie.search(“apple”); // returns true
trie.search(“app”); // returns false
trie.startsWith(“app”); // returns true
trie.insert(“app”);
trie.search(“app”); // returns true

//建立TrieNode类
class TrieNode {
    public char val;
    public boolean isWord; 
    public TrieNode[] children = new TrieNode[26];
    public TrieNode() {}
    TrieNode(char c){
        TrieNode node = new TrieNode();
        node.val = c;
    }
}

public class Trie {
    private TrieNode root;
    public Trie() {
        root = new TrieNode();
        root.val = ' ';
    }

    public void insert(String word) {
        TrieNode ws = root;
        for(int i = 0; i < word.length(); i++){
            char c = word.charAt(i);
            if(ws.children[c - 'a'] == null){
                ws.children[c - 'a'] = new TrieNode(c);
            }
            ws = ws.children[c - 'a'];
        }
        ws.isWord = true;
    }

    public boolean search(String word) {
        TrieNode ws = root; 
        for(int i = 0; i < word.length(); i++){
            char c = word.charAt(i);
            if(ws.children[c - 'a'] == null) return false;
            ws = ws.children[c - 'a'];
        }
        return ws.isWord;
    }

    public boolean startsWith(String prefix) {
        TrieNode ws = root; 
        for(int i = 0; i < prefix.length(); i++){
            char c = prefix.charAt(i);
            if(ws.children[c - 'a'] == null) return false;
            ws = ws.children[c - 'a'];
        }
        return true;
    }
}