Which is faster: an array or a hash?

Access speed depends on the operation:

• Access by index (array) or key (hash):

  • Array: O(1) - direct access by numerical index.
  • Hash: On average O(1), in the worst case O(n) - computing the hash of the key and searching in the hash table.

• Searching for an element by value:

  • Array: O(n) - sequential traversal.
  • Hash: Not designed for direct value search.

• Insertion/deletion:

  • Array: O(n) in the middle, O(1) at the end.
  • Hash: On average O(1).

Conclusion: Hash access by index or key generally works faster. Searching by value or inserting/deleting in the middle of an array is slower.

Thus, "what is faster" depends on the specific use case.