Introduction

In this blog post, we will explore how to solve the LeetCode problem "504" 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

Given an integer num, return a string of its base 7 representation. Example 1: Input: num = 100 Output: "202" Example 2: Input: num = -7 Output: "-10" Constraints: -107 <= num <= 107

Explanation

Here's the breakdown of the solution:

• Handle Negative Numbers: Store the sign of the number and work with its absolute value.
• Repeated Division: Repeatedly divide the absolute value of the number by 7, storing the remainders. These remainders, when read in reverse order, form the base 7 representation.

• Construct the String: Build the string representation using the remainders and prepend the sign if necessary.

• Runtime Complexity: O(log7(n)), where n is the input number. This is because the number of divisions required is logarithmic with base 7. Storage Complexity: O(log7(n)) to store the remainders in the list, which will be proportional to the number of digits in base 7.

Code

    def convertToBase7(num: int) -> str:
    """
    Given an integer num, return a string of its base 7 representation.
    """
    if num == 0:
        return "0"

    negative = num < 0
    num = abs(num)

    digits = []
    while num > 0:
        digits.append(str(num % 7))
        num //= 7

    result = "".join(digits[::-1])

    if negative:
        result = "-" + result

    return result