2015 contest easy challenge on Codility solution
Task description: You would like to set a password for a bank account. However, there are three restrictions on the format of the password:
it has to contain only alphanumerical characters (a−z, A−Z, 0−9); there should be an even number of letters; there should be an odd number of digits. You are given a string S consisting of N characters. String S can be divided into words by splitting it at, and removing, the spaces. The goal is to choose the longest word that is a valid password. You can assume that if there are K spaces in string S then there are exactly K + 1 words.
For example, given "test 5 a0A pass007 ?xy1", there are five words and three of them are valid passwords: "5", "a0A" and "pass007". Thus the longest password is "pass007" and its length is 7. Note that neither "test" nor "?xy1" is a valid password, because "?" is not an alphanumerical character and "test" contains an even number of digits (zero).
Write a function:
def solution(S)
that, given a non-empty string S consisting of N characters, returns the length of the longest word from the string that is a valid password. If there is no such word, your function should return −1.
For example, given S = "test 5 a0A pass007 ?xy1", your function should return 7, as explained above.
Assume that:
N is an integer within the range [1..200]; string S consists only of printable ASCII characters and spaces. In your solution, focus on correctness. The performance of your solution will not be the focus of the assessment.