Consolidating the structural and performance differences between Arrays and Linked Lists.
- Having defined the decision criteria based on balancing access versus modification costs, we now consolidate these concepts and structural differences into a final, comprehensive comparison.
- This table serves as a quick reference, summarizing structural characteristics, memory overhead, and the resultant time complexities for all key operations involving $n$ elements.
- The primary trade-off is between the Array's O(1) random access due to contiguity and the Linked List's O(1) modification when the insertion point is known.
Array vs. Linked List Comparison
| Feature | Array | Linked List (Singly) | Key Takeaway |
|---|---|---|---|
| Physical Storage | Contiguous memory block. | Scattered locations, linked by pointers. | Affects memory locality and random access. |
| Size/Growth | Typically fixed (requires reallocation to change size). | Highly dynamic; grows/shrinks easily. | Flexibility vs. guaranteed contiguous space. |
| Pointer Overhead | $O(1)$ (None) | $O(n)$ | Every Node_Structure requires pointer storage. |
| Space Complexity | $O(n)$ | $O(n)$ | Both are linear, but Array has a smaller constant factor. |
| Visit/Access (Index $i$) | $O(1)$ | $O(n)$ | Linked lists must traverse from NULL or head. |
| Add/Delete (Known $i$) | $O(n)$ (Requires data shifting) | $O(1)$ | LL is superior for modification (if location is known). |
| Memory Locality | Excellent | Poor | High locality generally leads to better cache performance. |