Remove Palindromic Subsequences

Intuition

If the string is empty, return 0.
If the string is already a palindromic string, return 1.
If the string is not palindromic, then there must be 2 letters in the string and we could not solve this problem in less than 2 steps. But we could solve it in exactly 2 steps by first remove all a s and then all b s.

Solution


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