Autocomplete System with Trie in DSA Javascript - Cheat Sheet & Quick Revision

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 quickly find words with common prefixes.

beginner

How does a Trie help in implementing an autocomplete system?

A Trie allows fast lookup of all words that start with a given prefix by traversing nodes corresponding to the prefix characters, then collecting all descendant words.

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 in the Trie.

intermediate

Explain how to search for all words with a given prefix in a Trie.

First, traverse the Trie nodes for each character in the prefix. If the prefix exists, perform a depth-first search from that node to collect all complete words below it.

beginner

What is a common way to store children nodes in a Trie node in JavaScript?

Children nodes are often stored in a JavaScript Map or an object where keys are characters and values are child nodes, allowing quick access to next characters.

What does each node in a Trie represent?

A A number

B A whole word

C A character of a word

D A sentence

Each node in a Trie represents a single character of a word.

What is the main advantage of using a Trie for autocomplete?

A Fast prefix search

B Uses less memory than arrays

C Sorts words automatically

D Stores only numbers

Trie allows fast search for words starting with a given prefix, which is key for autocomplete.

Which data structure is commonly used to store children in a Trie node in JavaScript?

A Stack

B Array

C Set

D Map

A Map is commonly used to store children nodes keyed by characters for quick access.

What is the time complexity to search for a prefix of length n in a Trie?

A O(n)

B O(1)

C O(n^2)

D O(log n)

Searching for a prefix of length n requires traversing n nodes, so O(n).

After finding the prefix node in a Trie, what is the next step to get autocomplete suggestions?

A Delete the prefix node

B Perform a depth-first search to collect all words

C Insert new words

D Sort the prefix node

We perform a depth-first search from the prefix node to find all complete words below it.

Describe how to build an autocomplete system using a Trie.

Think about storing words and searching by prefix.

Explain the process to find all words starting with a given prefix in a Trie.

Focus on prefix traversal and collecting words.