Recall & Review
beginner
What is a Trie data structure?
A Trie is a tree-like data structure that stores a dynamic set of strings, where each node represents a character. It is used to efficiently search for words with common prefixes.
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beginner
How does a Trie help in implementing autocomplete?
A Trie allows quick lookup of all words starting with a given prefix by traversing nodes matching the prefix, then collecting all descendant words.
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intermediate
What is the time complexity to insert a word of length n into a Trie?
The time complexity is O(n), where n is the length of the word, because each character is inserted one by one along the path.
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intermediate
Explain how to find all words with a given prefix in a Trie.
First, traverse the Trie nodes matching the prefix characters. Then, from the last node, perform a depth-first search to collect all complete words below it.
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intermediate
Why is Trie preferred over hash maps for autocomplete systems?
Trie stores words in a prefix-sharing way, saving space and allowing prefix queries efficiently. Hash maps do not support prefix search directly.
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What does each node in a Trie represent?
✗ Incorrect
Each node in a Trie represents a single character of a word.
What is the first step to find autocomplete suggestions in a Trie?
✗ Incorrect
You first traverse the Trie nodes that match the prefix to reach the subtree of possible completions.
What is the worst-case time complexity to search for a prefix of length n in a Trie?
✗ Incorrect
Searching for a prefix of length n requires traversing n nodes, so O(n).
Which of these is NOT a benefit of using Trie for autocomplete?
✗ Incorrect
Trie can use more memory than other structures in some cases, so it is not always memory efficient.
After reaching the prefix node in a Trie, what algorithm is commonly used to find all suggestions?
✗ Incorrect
Depth-first search is used to explore all descendant nodes to collect complete words.
Describe how you would implement an autocomplete system using a Trie.
Think about storing words and searching by prefix.
You got /4 concepts.
Explain the advantages and disadvantages of using a Trie for autocomplete.
Consider speed and memory trade-offs.
You got /4 concepts.