Introduction

In this blog post, we will explore how to solve the LeetCode problem "3467" 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. Transform nums by performing the following operations in the exact order specified: Replace each even number with 0. Replace each odd numbers with 1. Sort the modified array in non-decreasing order. Return the resulting array after performing these operations. Example 1: Input: nums = [4,3,2,1] Output: [0,0,1,1] Explanation: Replace the even numbers (4 and 2) with 0 and the odd numbers (3 and 1) with 1. Now, nums = [0, 1, 0, 1]. After sorting nums in non-descending order, nums = [0, 0, 1, 1]. Example 2: Input: nums = [1,5,1,4,2] Output: [0,0,1,1,1] Explanation: Replace the even numbers (4 and 2) with 0 and the odd numbers (1, 5 and 1) with 1. Now, nums = [1, 1, 1, 0, 0]. After sorting nums in non-descending order, nums = [0, 0, 1, 1, 1]. Constraints: 1 <= nums.length <= 100 1 <= nums[i] <= 1000

Explanation

• In-place Transformation: Iterate through the input array and replace even numbers with 0 and odd numbers with 1 directly within the original array.
  • Counting Sort Optimization: Instead of using a general-purpose sorting algorithm, leverage the fact that we only have two distinct values (0 and 1) to perform a counting sort. Count the occurrences of 0s and 1s.
  • Reconstruction: Rebuild the sorted array based on the counts of 0s and 1s.

• Runtime Complexity: O(n), where n is the length of the input array. Storage Complexity: O(1) - constant extra space.

Code

    def transform_array(nums):
    """
    Transforms an array by replacing even numbers with 0, odd numbers with 1,
    and then sorting the modified array in non-decreasing order.

    Args:
        nums: A list of integers.

    Returns:
        A list of integers representing the transformed and sorted array.
    """

    zeros = 0
    ones = 0

    # Count the number of 0s and 1s after transformation.
    for i in range(len(nums)):
        if nums[i] % 2 == 0:
            nums[i] = 0
            zeros += 1
        else:
            nums[i] = 1
            ones += 1

    # Reconstruct the array with sorted 0s and 1s.
    for i in range(len(nums)):
        if i < zeros:
            nums[i] = 0
        else:
            nums[i] = 1

    return nums