Introduction

In this blog post, we will explore how to solve the LeetCode problem "2444" 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 and two integers minK and maxK. A fixed-bound subarray of nums is a subarray that satisfies the following conditions: The minimum value in the subarray is equal to minK. The maximum value in the subarray is equal to maxK. Return the number of fixed-bound subarrays. A subarray is a contiguous part of an array. Example 1: Input: nums = [1,3,5,2,7,5], minK = 1, maxK = 5 Output: 2 Explanation: The fixed-bound subarrays are [1,3,5] and [1,3,5,2]. Example 2: Input: nums = [1,1,1,1], minK = 1, maxK = 1 Output: 10 Explanation: Every subarray of nums is a fixed-bound subarray. There are 10 possible subarrays. Constraints: 2 <= nums.length <= 105 1 <= nums[i], minK, maxK <= 106

Explanation

Here's a solution to the problem of finding the number of fixed-bound subarrays:

• Sliding Window Approach: Use a sliding window to iterate through the array. The window expands until it contains both minK and maxK.
• Track Indices: Keep track of the most recent indices of minK and maxK within the current window. Also, track the index of the most recent element outside the valid range (minK to maxK).

• Count Valid Subarrays: When both minK and maxK are within the window, the number of valid subarrays ending at the current index is determined by the minimum of the indices of the most recent minK and maxK minus the index of the element outside the valid range.

• Time Complexity: O(n), where n is the length of the input array. Space Complexity: O(1).

Code

    def count_fixed_bound_subarrays(nums, minK, maxK):
    """
    Counts the number of fixed-bound subarrays in the given array.

    Args:
        nums: The input integer array.
        minK: The minimum value in the fixed-bound subarray.
        maxK: The maximum value in the fixed-bound subarray.

    Returns:
        The number of fixed-bound subarrays.
    """

    count = 0
    min_index = -1
    max_index = -1
    left_bound = -1  # Index of the most recent element outside the valid range

    for i, num in enumerate(nums):
        if num < minK or num > maxK:
            left_bound = i
        if num == minK:
            min_index = i
        if num == maxK:
            max_index = i

        if min_index != -1 and max_index != -1:
            start = max(min_index, max_index)
            count += max(0, start - left_bound)  # Ensure the count is non-negative

    return count