Trie vs Hash Map for Prefix Matching in DSA Javascript - Key Differences

Recall & Review

beginner

What is a Trie data structure?

A Trie is a tree-like data structure that stores strings by sharing common prefixes. Each node represents a character, and paths from root to nodes form words.

beginner

How does a Hash Map store data for prefix matching?

A Hash Map stores key-value pairs where keys are usually full strings. It does not inherently support prefix search, so prefix matching requires checking keys manually or storing prefixes as keys.

intermediate

Why is Trie more efficient than Hash Map for prefix matching?

Trie allows direct traversal along characters of the prefix, making prefix search fast and efficient. Hash Map requires checking all keys or storing all prefixes, which is slower and uses more space.

intermediate

What is a downside of using Trie compared to Hash Map?

Trie can use more memory because it stores nodes for each character, even if some prefixes are rare. Hash Map uses memory only for stored keys but is slower for prefix queries.

intermediate

In what scenario is Hash Map preferred over Trie for prefix matching?

When the dataset is small or prefix queries are rare, Hash Map is simpler and uses less memory. Also, if only exact matches are needed, Hash Map is faster and easier to implement.

Which data structure is designed to efficiently support prefix matching?

A Stack

B Hash Map

C Trie

D Queue

Trie stores characters in a tree structure allowing fast prefix traversal.

What is a main disadvantage of using a Hash Map for prefix matching?

A No key-value pairs

B High memory usage for prefixes

C Cannot store strings

D Slow prefix search

Hash Map does not support prefix search natively, making it slow for that purpose.

Which data structure uses more memory due to storing nodes for each character?

A Trie

B Array

C Hash Map

D Linked List

Trie stores nodes for every character, which can increase memory usage.

When is Hash Map preferred over Trie?

A When only exact matches are needed

B When prefix queries are frequent

C When dataset is large

D When memory is unlimited

Hash Map is simpler and faster for exact matches without prefix queries.

What does each node in a Trie represent?

A A full word

B A character

C A number

D A key-value pair

Each node in a Trie represents a single character.

Explain how a Trie supports prefix matching compared to a Hash Map.

Think about how each data structure stores and searches strings.

List advantages and disadvantages of using Trie versus Hash Map for prefix matching.

Consider speed and memory trade-offs.