Custom Hash Map data structure implementation

An ASCII representation of the structure

[INDEX]      [BUCKET ARRAY]          [LINKED LIST NODES]

 0       |      •-------|------> [ Key: "Apple" | Val: 5 ] -> [ Key: "Grape" | Val: 2 ] -> NULL
         |              |
 1       |    EMPTY     |
         |              |
 2       |      •-------|------> [ Key: "Banana" | Val: 12 ] -> NULL
         |              |
 3       |      •-------|------> [ Key: "Pear" | Val: 8 ] -> [ Key: "Mango" | Val: 3 ] -> NULL
         |              |
 4       |    EMPTY     |

Performance Time Complexity

Average Case: $O(1)$ for insertions, deletions, and lookups.Worst Case: $O(n)$ if the hash function distributes keys poorly, causing all entries to collide into a single linked list.