leetcode 208. Implement Trie (Prefix Tree)-优快云博客

本文介绍了一种使用Trie树的数据结构实现，包括插入(insert)、搜索(search)和前缀匹配(startsWith)等基本操作。该实现假设所有输入由小写字母a-z组成。

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Implement a trie with insert, search, and startsWith methods.

Note:
You may assume that all inputs are consist of lowercase letters a-z.

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public class Trie {
    private class node{
        boolean mark;
        char val;
        node(char mchar){
            val=mchar;
        }
        node[] children=new node[26];
    }
    private node root;
    public Trie() {
        root = new node(' ');
    }

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

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

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

}