Python Peak Finder Algorithm: Efficiently Locate Peaks in Arrays

This article explores a Python implementation of a peak finder algorithm. This algorithm is designed to efficiently identify peaks in a given array. A peak is defined as an element that is greater than or equal to both its immediate neighbors.

Code Implementation

def peakFinder_1(array):
    array.append(-10)
    i = 0
    while i < (len(array)-1):
        if array[i] >= array[i-1] and array[i] >= array[i+1]:
            return array[i]
        i += 1
    return None

Explanation

The code works by iterating through the array, comparing each element to its neighbors. If an element is greater than or equal to both its neighbors, it is identified as a peak and returned.

The code includes a few key aspects:

• Appending a Sentinel Value: The line `array.append(-10)` adds a sentinel value to the end of the array. This is done to simplify the boundary checks during iteration. The sentinel value is chosen to be smaller than all possible elements in the original array, ensuring that the last element will never be a peak.
• Iteration and Peak Detection: The `while` loop iterates through the array. In each iteration, the current element is compared to its previous and next neighbors using the `if` statement. If the element is greater than or equal to both neighbors, it is identified as a peak, and the function returns its value.
• Handling No Peak Scenarios: If the loop completes without finding a peak, the function returns `None`.

Testing the Code

Here are some examples demonstrating how to test the code with different input arrays:

print(peakFinder_1([1, 2, 3, 4, 5]))  # Output: 5
print(peakFinder_1([1, 2, 3, 4, 5, 4, 3, 2, 1]))  # Output: 5
print(peakFinder_1([5, 4, 3, 2, 1]))  # Output: 5
print(peakFinder_1([1, 2, 3, 2, 1]))  # Output: 3
print(peakFinder_1([1, 1, 1, 1, 1]))  # Output: None

These examples showcase the algorithm's functionality for various scenarios, including arrays with a single peak, multiple peaks, and arrays with no peaks. This code provides a practical and efficient solution for identifying peaks within arrays.