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Introduction to Hashing
Implementing Hashtables in Different Languages
Different programming languages provide built-in implementations of Hashtables.
| Language | API (Hashtable Implementation) |
|---|---|
| Java | java.util.HashMap |
| Python | dict |
| C++ | std::unordered_map |
| JavaScript | Object or Map |
| C# | Dictionary<TKey, TValue> |
| Go | map |
Code Examples
Python3
Python3
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Limitations of Hashtables
Although Hashtables are incredibly fast and efficient, they come with some drawbacks.
| Limitation | Explanation |
|---|---|
| High Memory Usage | Hashtables require extra memory to store keys, values, and handle collisions. |
| No Ordering | Unlike arrays or linked lists, Hashtables do not maintain insertion order. |
| Performance Degradation | If too many collisions occur, lookup time can degrade from O(1) to O(n). |
| Resizing Cost | When 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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Implementing Hashtables in Different Languages
Code Examples
Limitations of Hashtables