374) Guess number higher or lower.py

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

class Solution:
    def guessNumber(self, n: int) -> int:
        low = 1
        high = n
        while low <= high:
            mid = low + (high - low) //2
            res = guess(mid)
            if res == 0:
                return mid
            elif res < 0:
                high = mid -1
            else:
                low = mid + 1