Grokking the Engineering Manager Coding Interview
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Introduction to Hashing
Table of Contents

Implementing Hashtables in Different Languages

Code Examples

Limitations of Hashtables

Implementing Hashtables in Different Languages

Different programming languages provide built-in implementations of Hashtables.

LanguageAPI (Hashtable Implementation)
Javajava.util.HashMap
Pythondict
C++std::unordered_map
JavaScriptObject or Map
C#Dictionary<TKey, TValue>
Gomap

Code Examples

Python3
Python3
. . . .

Limitations of Hashtables

Although Hashtables are incredibly fast and efficient, they come with some drawbacks.

LimitationExplanation
High Memory UsageHashtables require extra memory to store keys, values, and handle collisions.
No OrderingUnlike arrays or linked lists, Hashtables do not maintain insertion order.
Performance DegradationIf too many collisions occur, lookup time can degrade from O(1) to O(n).
Resizing CostWhen resizing occurs, all elements need to be rehased, causing a temporary slowdown.

Let's start solving the coding problems on Hashtables.

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Table of Contents

Implementing Hashtables in Different Languages

Code Examples

Limitations of Hashtables