Learn how we might create arguably the most used data structure in the world: the dynamic array (also known as the array list).
A dynamic array, also known as an array list, is a data structure that combines the advantages of arrays and linked lists. Unlike a standard array, a dynamic array can grow and shrink in size dynamically, allowing for more flexible and efficient memory usage.
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Dynamic Sizing:
- Automatically resizes when the capacity is exceeded.
- Reduces the need to know the upper limit of elements in advance.
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Efficient Indexing:
- Provides O(1) time complexity for accessing elements by index, similar to standard arrays.
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Amortized Time Complexity:
- Insertion at the end of the array takes O(1) amortized time, making it efficient for dynamic growth.
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Initialization:
- Start with a fixed-size array.
- Track the current number of elements and the total capacity.
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Insertion:
- If the array is full, create a new array with double the capacity.
- Copy existing elements to the new array.
- Insert the new element.
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Resizing:
- Doubling the capacity ensures that insertion operations remain efficient on average (amortized O(1) time complexity).
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Deletion:
- Remove the element and shift subsequent elements left, if necessary.
- Optionally, resize the array to reduce unused space.
Dynamic arrays or array lists provide a flexible and efficient way to manage collections of data. They combine the benefits of arrays and linked lists, making them one of the most commonly used data structures in programming.