Introduction

In this blog post, we will explore how to solve the LeetCode problem "168" 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 columnNumber, return its corresponding column title as it appears in an Excel sheet. For example: A -> 1 B -> 2 C -> 3 ... Z -> 26 AA -> 27 AB -> 28 ... Example 1: Input: columnNumber = 1 Output: "A" Example 2: Input: columnNumber = 28 Output: "AB" Example 3: Input: columnNumber = 701 Output: "ZY" Constraints: 1 <= columnNumber <= 231 - 1

Explanation

Here's the breakdown of the solution:

• Base-26 Conversion: The problem is essentially converting a base-10 number to a base-26 number, where 'A' represents 1, 'B' represents 2, and so on, up to 'Z' representing 26.
• Remainder and Division: We repeatedly take the remainder of the column number when divided by 26. This remainder (adjusted to be 0-25 instead of 1-26) gives us the rightmost character. Then, we divide the column number by 26 to get the remaining digits.

• Handle the 'Zero' Case: Since there is no '0' in Excel column titles, whenever the remainder is 0, it means it's 'Z'. We subtract 1 from the column number to account for this "borrowing" from the next higher digit.

• Time and Space Complexity: O(log₂₆(N)) time complexity, where N is the input number. O(log₂₆(N)) space complexity due to storing the characters in the result string.

Code

    def convertToTitle(columnNumber: int) -> str:
    result = ""
    while columnNumber > 0:
        columnNumber -= 1
        remainder = columnNumber % 26
        result = chr(ord('A') + remainder) + result
        columnNumber //= 26
    return result