|Problems? Is your data what you think it is?|
But just because hash key lookups/increments are O(1) operations, that doesn't make them computationally cheap.
An array lookup is also O(1), but it turns out it's a much computationally cheaper task to perform these array operations.
Hash is not O(1).
Also, this example of 0..999 integers looks too artifical to me, and it is too obvious to use an array here, so - for me - it does not deserve to even start the discussion, in the first place :)
I do appreciate good English of the original post, however, which I, personally, do not possess