Lintcode 442. Implement Trie (Prefix Tree) (Medium) (Python)

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本文详细介绍了一种高效的数据结构——字典树(Trie)，并提供了插入(insert)、搜索(search)和前缀查找(startsWith)的方法实现。通过具体示例展示了如何使用字典树进行单词的管理和检索，适用于字符串处理和词汇管理等场景。

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Implement Trie

Description:

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

Example
insert(“lintcode”)
search(“code”)

false
startsWith(“lint”)
true
startsWith(“linterror”)
false
insert(“linterror”)
search(“lintcode)
true
startsWith(“linterror”)
true
Notice
You may assume that all inputs are consist of lowercase letters a-z.

Code:

class TrieNode:
    def __init__(self):
        self.child = {}
        self.isWord = False

class Trie:

    def __init__(self):
        # do intialization if necessary
        self.root = TrieNode()
    """
    @param: word: a word
    @return: nothing
    """
    def insert(self, word):
        # write your code here
        cur = self.root
        for i in word:
            if i not in cur.child:
                newNode = TrieNode()
                cur.child[i] = newNode
                cur = newNode
            else:
                cur = cur.child[i]
        cur.isWord = True
    """
    @param: word: A string
    @return: if the word is in the trie.
    """
    def search(self, word):
        # write your code here
        cur = self.root
        for i in word:
            if i not in cur.child:
                return False
            cur = cur.child[i]
        return cur.isWord

    """
    @param: prefix: A string
    @return: if there is any word in the trie that starts with the given prefix.
    """
    def startsWith(self, prefix):
        # write your code here
        cur = self.root
        for i in prefix:
            print(i)
            if i not in cur.child:
                return False
            cur = cur.child[i]
        return True