Finding the first and last occurrence of a duplicate item in a sorted array using binary search. Also finds the count of duplicate element( and indices)

duplicateBinarySearch.py

#searchFirst is a flag not for finding the first/last occurence
def binarySearch(arr, l, r, x, searchFirst):

    result = -1
    while l <= r:

        mid = (l + r ) / 2

        # Check if x is present at mid
        if arr[mid] == x:
            result = mid
            if searchFirst:
                r = mid - 1
            else:
                l = mid + 1

        # If x is greater, ignore left half
        elif arr[mid] < x:
            l = mid + 1

        # If x is smaller, ignore right half
        else:
            r = mid - 1

    # If we reach here, then the element was not present
    return result


# Test array
arr = [2, 3, 4, 10, 10, 10, 10, 40]
x = 10

# Function call
first = binarySearch(arr, 0, len(arr) - 1, x, True)
last = binarySearch(arr, 0, len(arr) - 1, x, False)

if first == -1 and last == -1:
    print "Element not found"
else:
    print "First Occurence Index", first
    print "Last Occurence Index", last
    print "Total Occurence", (last - first + 1)