Difference Between Stack Using Array and Linked List​

A stack is a widely used linear data structure that operates on the Last In, First Out (LIFO) principle. Two common implementations of a stack are using arrays and linked lists. While both approaches provide the basic stack operations (push, pop, and peek), they differ in various aspects, such as memory usage, flexibility, and performance. Here, we explore these differences in detail.

Difference Between Stack Using Array and Linked List​

All Key points of Stack Using Array and Linked List​

Here’s a comparison of implementing a stack using an array and a linked list, with their respective strengths and weaknesses:

1. Ease of Implementation

  • Stack Using Array: Simple to implement because of the fixed size. Requires only basic array operations.
  • Stack Using Linked List: Slightly more complex to implement due to the need for dynamic memory allocation and pointer manipulation. Requires knowledge of linked list operations.

Conclusion: Arrays are simpler to implement compared to linked lists.

2. Performance

  • Stack Using Array: Push and pop operations have a time complexity of O(1) as they involve modifying the top index. May require resizing (copying elements to a new array) in dynamic arrays, which takes O(n) time.
  • Stack Using Linked List: Push and pop operations also have a time complexity of O(1) since they involve modifying the head pointer. No resizing is needed, ensuring consistent performance.

Conclusion: Both implementations provide efficient push and pop operations, but resizing in arrays can impact performance.

3. Memory Overhead

  • Stack Using Array: Minimal overhead, as only the array and an integer for the top index are required.
  • Stack Using Linked List: Higher overhead due to the storage of additional pointers for each node.

Conclusion: Arrays have lower memory overhead compared to linked lists.

4. Memory Management

  • Stack Using Array: Requires a predefined size. Allocates a contiguous block of memory. Can lead to memory wastage if the predefined size is too large or stack overflow if the size is too small.
  • Stack Using Linked List:Does not require a predefined size. Dynamically allocates memory as elements are added. Efficient use of memory, as no space is wasted.

Conclusion: A linked list is more memory-efficient for dynamic stack operations.

5. Flexibility

  • Stack Using Array: Limited flexibility due to the fixed size. Resizing in dynamic arrays can be time-consuming.
  • Stack Using Linked List: Highly flexible as it grows and shrinks dynamically without any predefined limit.

Conclusion: Linked lists are more flexible for applications with unpredictable stack sizes

6. Applications
  • Stack Using Array: Suitable for scenarios where the maximum stack size is known in advance, such as parsing expressions or managing function calls in compilers.
  • Stack Using Linked List: Ideal for applications requiring frequent stack resizing, such as backtracking algorithms and depth-first search (DFS).

Comparison Table of Stack Using Array and Linked List​

Feature Stack Using Array Stack Using Linked List
Implementation Simple Complex
Time Complexity (Push/Pop) O(1) O(1)
Resizing Overhead Yes No
Memory Overhead Low High
Memory Usage Fixed and contiguous Dynamic and flexible
Flexibility Limited High
Conclusion: The choice between implementing a stack using an array or a linked list depends on the specific requirements of your application. If simplicity and low overhead are priorities, arrays are the better option. However, for dynamic and flexible memory usage, linked lists are more suitable. Understanding these differences can help you make an informed decision for optimal stack implementation.