Introduction

In this blog post, we will explore how to solve the LeetCode problem "1332" using AI. LeetCode is a popular platform for preparing for coding interviews, and with the help of AI tools like Chatmagic, we can generate solutions quickly and efficiently - helping you pass the interviews and get the job offer without having to study for months.

Problem Statement

You are 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. Note that a subsequence does not necessarily need to be contiguous. A string is called palindrome if is one that reads the same backward as well as forward. Example 1: Input: s = "ababa" Output: 1 Explanation: s is already a palindrome, so its entirety can be removed in a single step. Example 2: Input: s = "abb" Output: 2 Explanation: "abb" -> "bb" -> "". Remove palindromic subsequence "a" then "bb". Example 3: Input: s = "baabb" Output: 2 Explanation: "baabb" -> "b" -> "". Remove palindromic subsequence "baab" then "b". Constraints: 1 <= s.length <= 1000 s[i] is either 'a' or 'b'.

Explanation

Here's the breakdown of the solution:

• Palindrome Check: Determine if the input string s is already a palindrome. If it is, only one step is needed.
• Non-Palindrome Case: If s is not a palindrome, since it only contains 'a' and 'b', any subsequence of only 'a's or only 'b's will always be a palindrome. In the worst case, we can remove all 'a's in one step, leaving only 'b's, which also form a palindrome, thus requiring a second step.

• Empty String: If the input string is empty, return 0

• Runtime & Storage Complexity:

  • Runtime: O(n), where n is the length of the string s.
  • Storage: O(1).

Code

    def remove_palindrome_sub(s: str) -> int:
    """
    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.

    Args:
        s (str): The input string consisting of 'a' and 'b'.

    Returns:
        int: The minimum number of steps to make the string empty.
    """
    if not s:
        return 0

    if s == s[::-1]:
        return 1
    else:
        return 2