Introduction

In this blog post, we will explore how to solve the LeetCode problem "2119" 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

Reversing an integer means to reverse all its digits. For example, reversing 2021 gives 1202. Reversing 12300 gives 321 as the leading zeros are not retained. Given an integer num, reverse num to get reversed1, then reverse reversed1 to get reversed2. Return true if reversed2 equals num. Otherwise return false. Example 1: Input: num = 526 Output: true Explanation: Reverse num to get 625, then reverse 625 to get 526, which equals num. Example 2: Input: num = 1800 Output: false Explanation: Reverse num to get 81, then reverse 81 to get 18, which does not equal num. Example 3: Input: num = 0 Output: true Explanation: Reverse num to get 0, then reverse 0 to get 0, which equals num. Constraints: 0 <= num <= 106

Explanation

Here's a breakdown of the optimal approach, complexity analysis, and the Python code solution:

• High-Level Approach:

  • Handle the base case where num is 0.
  • Check if num has trailing zeros. If it does and num is not 0, it will always return false.
  • If none of the above conditions are met, it means the original number can be reversed twice to obtain itself again.

• Complexity Analysis:

  • Runtime Complexity: O(1) - The solution involves constant-time checks.
  • Storage Complexity: O(1) - No extra space is used.

Code

    def is_same_after_reversals(num: int) -> bool:
    """
    Given an integer num, reverse num to get reversed1, then reverse reversed1 to get reversed2.
    Return true if reversed2 equals num. Otherwise return false.
    """

    if num == 0:
        return True

    if num % 10 == 0:
        return False

    return True