Assuming that the number of digits used is not excessive, the worst-case cost for Radix Sort when sorting n keys with distinct key values is:

\Theta(n \log n)
  • \Theta(n)
  • \Theta(N)
  • \Theta(n^2)

It takes at least \log n digits to represent n distinct values.

The cost is number of digits times number of records.

In a reasonable implementation, the number of digits won't be much worse than \log n