Background

Different sites have different password requirements.

You have grown tired of having to think up new passwords to meet all the different rules, so you write a small piece of code to do all the thinking for you.

Kata Task

Return any valid password which matches the requirements.

Input:

• len = password must be this length

• flagUpper = must (or must not) contain UPPERCASE alpha
• flagLower = must (or must not) contain lowercase alpha
• flagDigit = must (or must not) contain digit

Notes

• Only alpha-numeric characters are permitted
• The same character cannot occur more than once in the password!
• All test cases guarantee that a valid password is possible