Guess Number Higher or Lower.py

# We are playing the Guess Game. The game is as follows:

# I pick a number from 1 to n. You have to guess which number I picked.

# Every time you guess wrong, I'll tell you whether the number is higher or lower.

# You call a pre-defined API guess(int num) which returns 3 possible results (-1, 1, or 0):

# -1 : My number is lower
#  1 : My number is higher
#  0 : Congrats! You got it!
# Example:
# n = 10, I pick 6.

# Return 6.

# The guess API is already defined for you.
# @param num, your guess
# @return -1 if my number is lower, 1 if my number is higher, otherwise return 0
# def guess(num):

class Solution(object):
    def guessNumber(self, n):
        """
        :type n: int
        :rtype: int
        """
        start = 1
        end = n
        while(start <= end):
            mid = start + (end-start)/2
            if guess(mid) == 0:
                return mid
            if guess(mid) == 1:
                start = mid+1
            else:
                end = mid-1