Introduction

In this blog post, we will explore how to solve the LeetCode problem "1668" 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

For a string sequence, a string word is k-repeating if word concatenated k times is a substring of sequence. The word's maximum k-repeating value is the highest value k where word is k-repeating in sequence. If word is not a substring of sequence, word's maximum k-repeating value is 0. Given strings sequence and word, return the maximum k-repeating value of word in sequence. Example 1: Input: sequence = "ababc", word = "ab" Output: 2 Explanation: "abab" is a substring in "ababc". Example 2: Input: sequence = "ababc", word = "ba" Output: 1 Explanation: "ba" is a substring in "ababc". "baba" is not a substring in "ababc". Example 3: Input: sequence = "ababc", word = "ac" Output: 0 Explanation: "ac" is not a substring in "ababc". Constraints: 1 <= sequence.length <= 100 1 <= word.length <= 100 sequence and word contains only lowercase English letters.

Explanation

Here's the breakdown of the solution:

• Iterative Search: The code iteratively checks for word repeated k times as a substring of sequence, starting with k = 1 and incrementing k.
• Substring Check: In each iteration, it constructs the repeated word (k times word) and uses the in operator to efficiently check if it's a substring of sequence.

• Maximization: It keeps track of the maximum k value for which the repeated word is a substring. If at any point the repeated word is not found, the loop terminates and the current maximum k is returned.

• Runtime Complexity: O(N M L), where N is the length of sequence, M is the length of word, and L is the maximum k-repeating value.

• Storage Complexity: O(M * L) , due to the temporary string created when repeating the word.

Code

    def maxRepeating(sequence: str, word: str) -> int:
    """
    Calculates the maximum k-repeating value of word in sequence.
    """
    max_k = 0
    k = 1
    while True:
        repeated_word = word * k
        if repeated_word in sequence:
            max_k = k
            k += 1
        else:
            break
    return max_k