Looks similar to the venerable Rosetta Code.

As others have pointed out, there doesn't seem to be any barrier to posting solutions to LeetCode problems, or Rosetta code problems, or problems from many other sources, here and inviting discussion. In fact, given the appalling quality of many questions posted here lately, that seems like a good idea. :)

I've done this sort of thing here in the past, for example:

• Tales from writing a RPN evaluator in Perl 5, Perl 6 and Haskell
• Five Ways to Reverse a String of Words (C#, Perl 5, Perl 6, Ruby, Haskell)
• Yet Another Rosetta Code Problem (Perl, Ruby, Python, Haskell, ...)
• Rosetta PGA-TRAM
• Rosetta code: Split an array into chunks
• Re^2: Perlplexation - foreach shoulda Known (Rosetta: Perl, Python, Ruby)
• Rosetta Dispatch Table (Interview Question)

Having admittedly just done a quick browse of LeetCode, I doubt I'd use it. While I always ask job applicants to write code, I prefer to ask them to write code related to our business, code that you can't google for canned solutions on the Internet. Moreover, as indicated at On Interviewing and Interview Questions, hiring is a tricky business: it's not just algorithm pop quiz, teamwork and interpersonal skills are vital.