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Solving Leetcode Interviews in Seconds with AI: Array With Elements Not Equal to Average of Neighbors

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3 min read

Introduction

In this blog post, we will explore how to solve the LeetCode problem "1968" 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 a 0-indexed array nums of distinct integers. You want to rearrange the elements in the array such that every element in the rearranged array is not equal to the average of its neighbors. More formally, the rearranged array should have the property such that for every i in the range 1 <= i < nums.length - 1, (nums[i-1] + nums[i+1]) / 2 is not equal to nums[i]. Return any rearrangement of nums that meets the requirements. Example 1: Input: nums = [1,2,3,4,5] Output: [1,2,4,5,3] Explanation: When i=1, nums[i] = 2, and the average of its neighbors is (1+4) / 2 = 2.5. When i=2, nums[i] = 4, and the average of its neighbors is (2+5) / 2 = 3.5. When i=3, nums[i] = 5, and the average of its neighbors is (4+3) / 2 = 3.5. Example 2: Input: nums = [6,2,0,9,7] Output: [9,7,6,2,0] Explanation: When i=1, nums[i] = 7, and the average of its neighbors is (9+6) / 2 = 7.5. When i=2, nums[i] = 6, and the average of its neighbors is (7+2) / 2 = 4.5. When i=3, nums[i] = 2, and the average of its neighbors is (6+0) / 2 = 3. Note that the original array [6,2,0,9,7] also satisfies the conditions. Constraints: 3 <= nums.length <= 105 0 <= nums[i] <= 105

Explanation

Here's the solution:

  • Sorting: Sort the input array nums. This brings elements with closer values next to each other.
  • Interleaving: Create a new array by interleaving the first half of the sorted array with the second half. This ensures that each element is placed between two elements that are significantly different from it. More formally, placing smaller and larger values alternatingly ensures no element equals to the average of its neighbors.

  • Time Complexity: O(n log n), due to sorting. Space Complexity: O(n), for the new array to store the result.

Code

    def rearrangeArray(nums):
    """
    Rearranges the elements in the array such that every element in the rearranged array
    is not equal to the average of its neighbors.

    Args:
        nums: A 0-indexed array of distinct integers.

    Returns:
        Any rearrangement of nums that meets the requirements.
    """

    n = len(nums)
    nums.sort()
    result = [0] * n
    left = 0
    right = n - 1
    for i in range(n):
        if i % 2 == 0:
            result[i] = nums[left]
            left += 1
        else:
            result[i] = nums[right]
            right -= 1
    return result

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