Introduction

In this blog post, we will explore how to solve the LeetCode problem "2951" 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 mountain. Your task is to find all the peaks in the mountain array. Return an array that consists of indices of peaks in the given array in any order. Notes: A peak is defined as an element that is strictly greater than its neighboring elements. The first and last elements of the array are not a peak. Example 1: Input: mountain = [2,4,4] Output: [] Explanation: mountain[0] and mountain[2] can not be a peak because they are first and last elements of the array. mountain[1] also can not be a peak because it is not strictly greater than mountain[2]. So the answer is []. Example 2: Input: mountain = [1,4,3,8,5] Output: [1,3] Explanation: mountain[0] and mountain[4] can not be a peak because they are first and last elements of the array. mountain[2] also can not be a peak because it is not strictly greater than mountain[3] and mountain[1]. But mountain [1] and mountain[3] are strictly greater than their neighboring elements. So the answer is [1,3]. Constraints: 3 <= mountain.length <= 100 1 <= mountain[i] <= 100

Explanation

Here's the approach to solve the problem:

• Iterate through the array: The solution iterates through the input array mountain from the second element (index 1) to the second-to-last element (index len(mountain) - 2). This is because the first and last elements cannot be peaks according to the problem definition.
• Peak Condition: Inside the loop, it checks if the current element is greater than its immediate neighbors (the element before and the element after it). If it is, the index of the current element is added to the result list.

• Return Result: After iterating through all the relevant elements, the function returns the list of peak indices.

• Runtime Complexity: O(n), where n is the length of the mountain array.

• Storage Complexity: O(p), where p is the number of peaks found (in the worst case, O(n) if almost all elements are peaks).

Code

    def find_peaks(mountain):
    """
    Finds all the peaks in a mountain array.

    Args:
        mountain: A 0-indexed array of integers.

    Returns:
        A list of indices of peaks in the given array.
    """

    peaks = []
    for i in range(1, len(mountain) - 1):
        if mountain[i] > mountain[i - 1] and mountain[i] > mountain[i + 1]:
            peaks.append(i)
    return peaks