Data structure for elements of 0 - N-1

Propose a data structure for the following:
- The data structure would hold elements from 0 to N-1.
There is no order on the elements (no ascending/descending order
requirement)

The complexity of the operations should be as follows:
* Initialization - O(1)
* Insertion of an element - O(1)
* Deletion of an element - O(1)
* Finding a element - O(1)
* Deleting all elements - O(1)

answer:

use an array (dynamically alloced) of size n.
and array[n] will indicate the count of an element.