SRM481 - div2 - level two

srm481_div2_level2.py

#! /usr/bin/env python
# -*- coding: utf-8 -*-

"""SRM481 - div2 - level two

This time, instead of solving an easy problem with a 
known solution, you will be in charge in solving an 
old problem with a solution which was unknown to 
this date. The old question is whether the egg or 
the chicken came first. This question has been very 
difficult to answer over the ages, but a chance has 
finally come: It is said that a new oracle has 
appeared which knows everything.

You tried asking the question to the oracle, but the 
oracle refused to answer, arguing that it has already 
answered the question to n other people and is tired 
of answering that question. Not to give up, you decided 
to interview each of the n people. Of them, eggCount 
people told you that the answer was "The egg", while 
the remaining n-eggCount people claimed that the answer 
was "The chicken". Confused by the results, you asked 
the oracle a second time. The oracle still refused to 
answer the question, but instead explained the results: 
In order to hide the truth to those unworthy, the oracle 
has intentionally given the wrong answer to exactly 
lieCount people. On the other hand, also to avoid 
sharing the secret, exactly liarCount people (not 
necessarily those that were told the right answer by 
the oracle) have intentionally given you the opposite 
answer to the one given to them by the oracle.

You are still suspiscious that the explanation given by 
the oracle is another lie. Given ints n, eggCount, 
lieCount and liarCount, find out if scenarios exist such 
that "The egg" or "The chicken" is the correct answer. If 
there exist scenarios such that either answer is correct, 
return "Ambiguous" (quotes for clarity). If only one answer 
has a possible scenario, return "The egg" or "The chicken" 
(quotes for clarity) depending on the answer. If neither 
of the answers has a possible scenario, return "The oracle 
is a lie". 

Definition:
    Class: ChickenOracle
    Method: theTruth
    Parameters: int, int, int, int
    Returns: String
    Method signature: String theTruth
        (int n, int eggCount, int lieCount, int liarCount)
"""

class ChickenOracle(object):
    """Chicken Oracle

    Constraints:
        - n will be between 1 and 1000000, inclusive.
        - eggCount, lieCount and liarCount will each be between 0 and n, inclusive. 

    >>> chickenoracle = ChickenOracle()
    >>> print chickenoracle.theTruth(10, 10, 0, 0)
    The egg
    >>> print chickenoracle.theTruth(60, 40, 0, 3)
    The oracle is a lie
    >>> print chickenoracle.theTruth(60, 20, 5, 25)
    The chicken
    >>> print chickenoracle.theTruth(1000, 500, 250, 250)
    Ambiguous
    """

    def __init__(self):
        pass

    def theTruth(self, n, eggCount, lieCount, liarCount):
        egg = False
        chicken = False
        
        if (eggCount + liarCount + lieCount - n) % 2 == 0:
            e = (eggCount + liarCount+lieCount - n) / 2
            if e >= 0 \
                    and e <= liarCount \
                    and e <= eggCount \
                    and liarCount-e <= n-eggCount:
                egg = True

        if (eggCount + liarCount - lieCount) % 2 == 0:
            c = (eggCount + liarCount - lieCount) / 2
            if c >= 0 \
                    and c <= liarCount \
                    and c <= eggCount \
                    and liarCount-c <= n-eggCount:
                chicken = True

        if egg and chicken: return "Ambiguous"
        if egg: return "The egg"
        if chicken: return "The chicken"
        return "The oracle is a lie";

if __name__ == '__main__':
    import doctest
    doctest.testmod()