Introduction

In this blog post, we will explore how to solve the LeetCode problem "1957" 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

A fancy string is a string where no three consecutive characters are equal. Given a string s, delete the minimum possible number of characters from s to make it fancy. Return the final string after the deletion. It can be shown that the answer will always be unique. Example 1: Input: s = "leeetcode" Output: "leetcode" Explanation: Remove an 'e' from the first group of 'e's to create "leetcode". No three consecutive characters are equal, so return "leetcode". Example 2: Input: s = "aaabaaaa" Output: "aabaa" Explanation: Remove an 'a' from the first group of 'a's to create "aabaaaa". Remove two 'a's from the second group of 'a's to create "aabaa". No three consecutive characters are equal, so return "aabaa". Example 3: Input: s = "aab" Output: "aab" Explanation: No three consecutive characters are equal, so return "aab". Constraints: 1 <= s.length <= 105 s consists only of lowercase English letters.

Explanation

Here's the breakdown of the solution:

• Iterate and Check: Iterate through the input string s.
• Maintain Result: Build a new string (result) character by character. If adding the current character would result in three consecutive identical characters in result, skip the current character. Otherwise, append the current character to result.

• Return Result: After processing the entire input string, return the result.

• Time Complexity: O(n), where n is the length of the input string.

• Space Complexity: O(n) in the worst case, as the result string could potentially store almost the entire input string.

Code

    def makeFancyString(s: str) -> str:
    """
    Given a string s, delete the minimum possible number of characters from s to make it fancy.
    A fancy string is a string where no three consecutive characters are equal.
    Return the final string after the deletion. It can be shown that the answer will always be unique.
    """
    result = ""
    for char in s:
        if len(result) >= 2 and result[-1] == char and result[-2] == char:
            continue  # Skip if adding 'char' would create three consecutive identical chars
        result += char

    return result