Ok, thanks.

Hi @Rockkley.

Lambdas are anonymous callable objects. If you want call it later, you must use a variable, no other choice to do that. And here (in codewars) if there no name, unit test cannot check the solution.

For your information, in python, a def (and so, a fonction) defined like that create a variable:

def foobar(): pass

The variable created is foobar, the proof, you can do that:

def foobar(): pass
foobar = 1234

It's the aim of the mechanism under the concept of decorators.

If you prefer i can use these solutions instead of lambda, the solution will be acepted:

# Common accepted solution
def check(s, e): return e in s

# Another solution
def singleton(c): return c()
@singleton
class check:
  def __call__(self, s, e):
    return e in s

With small arr, there can be no re-allocation.

We can improve that with a pre-allocated array: visited := make([int]*int, len(arr) - 1).

Yes sometimes using memory in the right way (when input data allow it) can greatly optimize a program like tables of sinus in ancient architechtures which hasn't got any mathematical processor.

A recursive version if not optimized at compile time generate extra assemby instruction for creating/destroying a stack context for a function call. The context contains temporary variable, caller arguments, and the return for the instruction pointer. Iterative version keeps the same stack context, no need to manage life cycle of called context, so it's faster cause less instructions to execute.

A teminal recusion can be easily optimized at compile time can be do by «de-recursivate», i.e. transform a recusive algorithm by an iterative one through the use of its own stack with a fast use of this stack. GCC do that for example.

I'd like that these languages to be added too: Smalltalk and Ada

Thank you.

Yeah, you are right. Sometimes i choose the easy way.

Maybe, iterative version is easy too: https://www.codewars.com/kata/reviews/5d6ddad7e78d210001f76504/groups/5d809b2c01af06000163ed61 .

bravo, beautiful algorithm !

Me too

.