Introduction

In this blog post, we will explore how to solve the LeetCode problem "3271" 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 of length n and an integer k, where n is a multiple of k. Your task is to hash the string s into a new string called result, which has a length of n / k. First, divide s into n / k substrings, each with a length of k. Then, initialize result as an empty string. For each substring in order from the beginning: The hash value of a character is the index of that character in the English alphabet (e.g., 'a' → 0, 'b' → 1, ..., 'z' → 25). Calculate the sum of all the hash values of the characters in the substring. Find the remainder of this sum when divided by 26, which is called hashedChar. Identify the character in the English lowercase alphabet that corresponds to hashedChar. Append that character to the end of result. Return result. Example 1: Input: s = "abcd", k = 2 Output: "bf" Explanation: First substring: "ab", 0 + 1 = 1, 1 % 26 = 1, result[0] = 'b'. Second substring: "cd", 2 + 3 = 5, 5 % 26 = 5, result[1] = 'f'. Example 2: Input: s = "mxz", k = 3 Output: "i" Explanation: The only substring: "mxz", 12 + 23 + 25 = 60, 60 % 26 = 8, result[0] = 'i'. Constraints: 1 <= k <= 100 k <= s.length <= 1000 s.length is divisible by k. s consists only of lowercase English letters.

Explanation

• Iterate through substrings: Divide the input string s into substrings of length k.
  • Calculate hash and append: For each substring, compute the sum of character hash values modulo 26, and append the corresponding character to the result.
  • Return result: Concatenate characters and return the resulting string.

• Runtime Complexity: O(n), Storage Complexity: O(n/k)

Code

    def string_hash(s: str, k: int) -> str:
    """
    Hashes a string s into a new string based on the given algorithm.

    Args:
        s: The input string.
        k: The length of each substring.

    Returns:
        The hashed string.
    """

    n = len(s)
    result = ""
    for i in range(0, n, k):
        substring = s[i:i + k]
        hash_sum = 0
        for char in substring:
            hash_sum += ord(char) - ord('a')
        hashed_char = hash_sum % 26
        result += chr(ord('a') + hashed_char)
    return result