Why does a HashSet provide faster lookup than a List for checking if an element exists?

Solution:Step 1: Understand HashSet internal structureHashSet uses a hash table which allows average constant time O(1) lookup.Step 2: Compare with List lookupList requires scanning elements linearly, O(n) time, slower for large collections.Final Answer:HashSet uses a hash table for O(1) average loo

[Solved] Why does a HashSet<T> provide faster lookup than a List<T> for checking if an element exists? - Ans: HashSet uses a hash table for O(1) average lookup time. | C Sharp (C#)

C Sharp (C#) - Collections

Why does a HashSet<T> provide faster lookup than a List<T> for checking if an element exists?

AHashSet stores elements in sorted order for binary search.

BList caches elements for faster repeated lookups.

CList uses a hash table internally, making it slower.

DHashSet uses a hash table for O(1) average lookup time.

Step-by-Step Solution

Solution:

Step 1: Understand HashSet internal structure
HashSet uses a hash table which allows average constant time O(1) lookup.
Step 2: Compare with List lookup
List requires scanning elements linearly, O(n) time, slower for large collections.
Final Answer:
HashSet uses a hash table for O(1) average lookup time. -> Option D
Quick Check:
HashSet lookup speed = O(1) via hash table [OK]

Quick Trick: HashSet lookup is fast due to hashing, unlike List [OK]

Common Mistakes:

MISTAKES

Thinking HashSet is sorted
Believing List uses hashing internally
Assuming List caches lookups

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Why does a HashSet<T> provide faster lookup than a List<T> for checking if an element exists?

Step 1: Understand HashSet internal structure

Step 2: Compare with List lookup

Final Answer:

Quick Check:

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