Challenge Name

Issue Description

User @AungMyoKyaw issued a pull request (#15856) to update Euler Project problem 4 in the interview prep section. Though the updated code in the pull request is correct and passes npm test, Travis CI throws the error Octal escape sequences are not allowed in strict mode. However, the error occurs due to a leading zero in the solution of the Create a Priority Queue problem in the data structures portion of the interview prep section.