minion_hierarchy.py

#!/usr/bin/env python

'''
Author: John D. Anderson (TigerJ)
Usage: minion_hierarchy -n integer
Origin: Google "foo.bar" project - Problem 1.1
Program Description:

    Minion hierarchy
    ================

    Rumor has it there's a mad scientist out there who had abducted hundreds of
    rabbits to test out a new zombie serum.

    Agent Beta Rabbit, spy and brilliant mathematician, storms in the room:
    "I know who's behind that plan. It's a man who calls himself Professor
    Boolean. My preliminary recon data shows that he's operating a lab
    somewhere on the islands near Silicon Valley. I also recently got a tip
    that Professor Boolean's lab minions have a certain hierarchical structure:
    Each manager has no more than 7 direct reports."

    Interesting... This information can help us estimate how many minions are
    working in this lab, and thus, the size of this operation. We need to know
    what we're facing here.

    Write a function called answer(x) that returns the maximum number of minion
    employees a company following the "no more than 7 direct reports" theory
    can have, with no more than x levels of supervision.

    You can assumet that:
    1. Professor Boolean is the highest level of supervision and has no
       manager.
    2. Each minion employee (other than Professor Boolean) has exactly one
       manager.

    For example, with no more than 1 level of supervision, we could have a
    maximum of 8 employees: Professor Boolean and his 7 reports.

    x will be a positive integer, not exceeding 10.

    Languages
    =========

    To provide a Python solution, edit solution.py
    To provide a Java solution, edit solution.java

    Test cases
    ==========

    Inputs:
        (int) x = 1
    Output:
        (int) 8

    Inputs:
        (int) x = 2
    Output:
        (int) 57

    Use verify [file] to test your solution and see how it does. When you are a
    finished editing your code, use submit [file] to submit your answer. If
    your solution passes the test cases, it will be removed from your home
    folder.
'''

# libs
import sys


# functions
def answer(x):
    y = 0
    for i in range(x+1):
        y += 7**i
    return y


# executable
if __name__ == '__main__':

    # usage message
    usage = '\nUsage: minion_hierarchy -n integer\n'

    # CLA check
    if len(sys.argv) > 1:
        if sys.argv[1] == '-n':
            print answer(int(sys.argv[2]))
            sys.exit()

        # wrong arguments passed
        else:
            sys.exit(usage)

    # no arguments passed
    sys.exit(usage)