Introduction

In this blog post, we will explore how to solve the LeetCode problem "670" 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 num. You can swap two digits at most once to get the maximum valued number. Return the maximum valued number you can get. Example 1: Input: num = 2736 Output: 7236 Explanation: Swap the number 2 and the number 7. Example 2: Input: num = 9973 Output: 9973 Explanation: No swap. Constraints: 0 <= num <= 108

Explanation

• Convert to String: Transform the integer into a string to easily manipulate individual digits.
  • Find Optimal Swap: Iterate through the string, searching for the rightmost digit to swap with the current digit to maximize the number.
  • Perform Swap: If a suitable swap is found, perform the swap and return the resulting integer.

• Runtime Complexity: O(N^2), where N is the number of digits in the input number. Storage Complexity: O(N) to store the string representation of the number.

Code

    def maximumSwap(num: int) -> int:
    """
    Given a non-negative integer, you could swap two digits at most once to get the maximum valued number.
    Return the maximum valued number you could get.

    Example 1:
    Input: num = 2736
    Output: 7236
    Explanation: Swap the number 2 and the number 7.

    Example 2:
    Input: num = 9973
    Output: 9973
    Explanation: No swap.

    Constraints:
    0 <= num <= 10^8
    """
    s = list(str(num))
    n = len(s)

    max_idx = -1
    idx1 = -1
    idx2 = -1

    for i in range(n):
        max_idx = i
        for j in range(i + 1, n):
            if s[j] >= s[max_idx]:
                max_idx = j

        if s[i] != s[max_idx]:
            idx1 = i
            idx2 = max_idx
            break

    if idx1 == -1:
        return num

    s[idx1], s[idx2] = s[idx2], s[idx1]
    return int("".join(s))