Trie

Question 1

What is a Trie?

Answer 1

A tree structure for storing strings with shared prefixes.

Use Case: Autocomplete, prefix search.

Question 2

What are the key steps to implement a Trie?

Answer 2

1. Create TrieNode with children dict.
2. Insert: Add chars to nodes, mark end.
3. Search: Traverse chars, check end.

Action: Explain steps for Implement Trie aloud.

Question 3

How does a Trie apply to Implement Trie?

Answer 3

Build trie for insert/search using node dict to store chars and track word ends.

Example: Implement Trie.

Question 4

What are the complexity and gotchas of a Trie?

Answer 4

Time complexity: O(m) for insert/search, Space complexity: O(m * n).
Gotchas include empty strings and case sensitivity.

Action: List edge cases for Implement Trie aloud.

Question 5

Code example of a Trie.

Answer 5

```python
from typing import Dict
class TrieNode:
def __init__(self) -> None:
self.children: Dict[str, ‘TrieNode’] = {}
self.is_end: bool = False
class Trie:
def __init__(self) -> None:
self.root = TrieNode()
def insert(self, word: str) -> None:
node = self.root
for char in word:
if char not in node.children:
node.children[char] = TrieNode()
node = node.children[char]
node.is_end = True
def search(self, word: str) -> bool:
node = self.root
for char in word:
if char not in node.children:
return False
node = node.children[char]
return node.is_end
~~~