Guess The Number : Binary Search Problem

guess_the_number.py

"""
Q1: Two friends, Elaine and Tom, are playing a guessing game with each other. 
Elaine thinks of an integer in her mind and Tom needs to guess the number. 
Tom can ask a question as follows: Is your number greater than or equal to 5 
(or any other specified integer)? 
Then Elaine has to reply yes or no based on the comparison results of the two numbers.  
Design an algorithm, in pseudo-code to help Tom find that number quick.

UAH CS 617 - Spring 2023
"""

"""
Strategy:
    1) First find lower and upper bounds to construct the search space
    2) Use binary search algorithm to find/guess the number in that bound
"""

def ask_elaine(N):
    if N<=-55: #if target number is gt or eq, then return True 
        return True 
    else:
        return False

def find_bounds(lower, upper):
    while 1:
        if ask_elaine(lower) and not(ask_elaine(upper)):
            return lower, upper
        else:
            if ask_elaine(lower) and ask_elaine(upper):
                lower=lower*10
                upper=upper*10
            elif not(ask_elaine(lower)) and not(ask_elaine(upper)):
                lower=lower-lower*10
                upper=upper-upper*10


def guess_the_number():
    lower, upper = find_bounds(-55,55)
    while lower <= upper:
        mid = int((lower+upper)/2)
        if ask_elaine(mid):
            lower=mid
        else:
            upper=mid

        if abs(upper-lower)==1:
                return lower 
        print(f"lower is {lower} upper is: {upper} \n")

print(guess_the_number())