Introduction

In this blog post, we will explore how to solve the LeetCode problem "3300" 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 an integer array nums. You replace each element in nums with the sum of its digits. Return the minimum element in nums after all replacements. Example 1: Input: nums = [10,12,13,14] Output: 1 Explanation: nums becomes [1, 3, 4, 5] after all replacements, with minimum element 1. Example 2: Input: nums = [1,2,3,4] Output: 1 Explanation: nums becomes [1, 2, 3, 4] after all replacements, with minimum element 1. Example 3: Input: nums = [999,19,199] Output: 10 Explanation: nums becomes [27, 10, 19] after all replacements, with minimum element 10. Constraints: 1 <= nums.length <= 100 1 <= nums[i] <= 104

Explanation

Here's the solution to the problem, focusing on efficiency:

• Digit Sum Calculation: Efficiently calculate the digit sum for each number by iteratively extracting digits using the modulo operator (%) and integer division (//).

• Finding Minimum: Iterate through the transformed array to find the minimum element.

• Time and Space Complexity: O(N * log(M)), where N is the number of elements in nums and M is the maximum value of the elements (due to the digit sum calculation). Space Complexity: O(1) - constant extra space.

Code

    def digit_sum(n):
    sum_digits = 0
    while n > 0:
        sum_digits += n % 10
        n //= 10
    return sum_digits

def minimum_digit_sum(nums):
    """
    Replaces each element in nums with the sum of its digits and returns the minimum element.
    """
    min_val = float('inf')
    for num in nums:
        digit_sum_val = digit_sum(num)
        min_val = min(min_val, digit_sum_val)
    return min_val