Binary search - find the last position

binary_search_last_position.py

def find_last_pos(arr, target):
    left = 0
    right = len(arr) - 1

    last_position = -1      # keep track of the latest valid mid position
    while left <= right:
        mid = left + (right - left) // 2
        if arr[mid] == target:
            last_position = mid
            left = mid + 1      # continue searching to the right
        elif arr[mid] < target:
            left = mid + 1
        else:
            right = mid - 1

    return last_position