Introduction

In this blog post, we will explore how to solve the LeetCode problem "2856" 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 array num sorted in non-decreasing order. You can perform the following operation any number of times: Choose two indices, i and j, where nums[i] < nums[j]. Then, remove the elements at indices i and j from nums. The remaining elements retain their original order, and the array is re-indexed. Return the minimum length of nums after applying the operation zero or more times. Example 1: Input: nums = [1,2,3,4] Output: 0 Explanation: Example 2: Input: nums = [1,1,2,2,3,3] Output: 0 Explanation: Example 3: Input: nums = [1000000000,1000000000] Output: 2 Explanation: Since both numbers are equal, they cannot be removed. Example 4: Input: nums = [2,3,4,4,4] Output: 1 Explanation: Constraints: 1 <= nums.length <= 105 1 <= nums[i] <= 109 nums is sorted in non-decreasing order.

Explanation

Here's a breakdown of the solution:

• Pairing Strategy: The core idea is to remove elements by pairing the smallest with the largest possible element in the sorted array, as long as they are not equal. This approach guarantees the maximal number of removals. Since the array is sorted, we can use two pointers to achieve this pairing efficiently.
• Handling Equality: If at any point the remaining elements are all equal, no further removals are possible. The loop terminates when the left and right pointers meet, or when nums[left] >= nums[right].

• Returning the Result: The final length of the array after the removals is simply right - left + 1.

• Complexity: O(n) runtime, O(1) storage.

Code

    def min_length_after_removals(nums):
    """
    Calculates the minimum length of nums after applying the removal operations.

    Args:
        nums: A list of integers sorted in non-decreasing order.

    Returns:
        The minimum length of nums after applying the operation zero or more times.
    """

    left, right = 0, len(nums) - 1

    while left < right:
        if nums[left] < nums[right]:
            left += 1
            right -= 1
        else:
            break

    return right - left + 1