Peak element Python

PROGRAM TO FIND THE PEAK ELEMENT IN AN ARRAY

An array element is a peak if it is NOT smaller than its neighbours. For corner elements, we need to consider only one neighbour.

# A binary search based function 

# that returns index of a peak element

def findPeakUtil(arr, low, high, n):

      

     # Find index of middle element

     # (low + high)/2 

     mid = low + (high - low)/2 

     mid = int(mid)

      

    # Compare middle element with its 

    # neighbours (if neighbours exist)

    if ((mid == 0 or arr[mid - 1] <= arr[mid]) and 

        (mid == n - 1 or arr[mid + 1] <= arr[mid])):

        return mid

  

  

    # If middle element is not peak and 

    # its left neighbour is greater 

    # than it, then left half must 

    # have a peak element

    elif (mid > 0 and arr[mid - 1] > arr[mid]):

        return findPeakUtil(arr, low, (mid - 1), n)

  

    # If middle element is not peak and

    # its right neighbour is greater

    # than it, then right half must 

    # have a peak element

    else:

        return findPeakUtil(arr, (mid + 1), high, n)

  

  

# A wrapper over recursive 

# function findPeakUtil()

def findPeak(arr, n):

  

    return findPeakUtil(arr, 0, n - 1, n)

  

  

# Driver code

arr = [1, 3, 20, 4, 1, 0]

n = len(arr)

print("Index of a peak point is", findPeak(arr, n))

OUTPUT

Index of a peak point is 2

CREDITS:  https://www.geeksforgeeks.org/find-a-peak-in-a-given-array/