1332.RemovePalindromicSubsequences.py

'''
    Given a string s consisting only of letters 'a' and 'b'. 
    In a single step you can remove one palindromic 
    subsequence from s.

    Return the minimum number of steps to make the given 
    string empty.

    A string is a subsequence of a given string, if it is 
    generated by deleting some characters of a given string 
    without changing its order.

    A string is called palindrome if is one that reads the 
    same backward as well as forward.

    Example:
    Input: s = "ababa"
    Output: 1
    Explanation: String is already palindrome

    Example:
    Input: s = "abb"
    Output: 2
    Explanation: "abb" -> "bb" -> "". 
                 Remove palindromic subsequence "a" then "bb".

    Example:
    Input: s = "baabb"
    Output: 2
    Explanation: "baabb" -> "b" -> "". 
                 Remove palindromic subsequence "baab" then "b".

    Example:
    Input: s = ""
    Output: 0

    Constraints:
        - 0 <= s.length <= 1000
        - s only consists of letters 'a' and 'b'
'''
#Difficulty: Easy
#49 / 49 test cases passed.
#Runtime: 32 ms
#Memory Usage: 14.1 MB

#Runtime: 32 ms, faster than 58.63% of Python3 online submissions for Remove Palindromic Subsequences.
#Memory Usage: 14.1 MB, less than 90.00% of Python3 online submissions for Remove Palindromic Subsequences.

class Solution:
    def removePalindromeSub(self, s: str) -> int:
        if not s:
            return 0
        elif s == s[::-1]:
            return 1
        else:
            return 2