Programming tips

Some time ago I was interviewed to one of the Java-based projects and I was asked to solve this pretty interesting puzzle. The question was "how to count frequency of a digit in a factorial of number, let’s say 1000". I tried to solve it using Java 8 Stream API, but I guess you see how bad decision it was. Problems like that can be easily solved with pure functional languages and today we are going to find out how to solve this puzzle with Haskell.