[leetCode] 374. Guess Number Higher or Lower (Python)

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 will tell you whether the number I picked is higher or lower than your guess.

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

• -1: The number I picked is lower than your guess (i.e. pick > num).
• 1: The number I picked is higher than your guess (i.e. pick < num).
• 0: The number I picked is equal to your guess (i.e. pick == num).

Return the number that I picked.

 

Example 1:

Input: n = 10, pick = 6
Output: 6

Example 2:

Input: n = 1, pick = 1
Output: 1

Example 3:

Input: n = 2, pick = 1
Output: 1

Example 4:

Input: n = 2, pick = 2
Output: 2

Constraints:

• 1 <= n <= 231 - 1
• 1 <= pick <= n

Solution

# 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: int) -> int:

class Solution:
    def guessNumber(self, n: int) -> int:
        left, right = 1, n
        
        while True:
            middle_num = int((left + right) / 2)
            if guess(middle_num) == 1:
                left = middle_num + 1
            elif guess(middle_num) == -1:
                right = middle_num - 1
            else:
                return middle_num

SOMJANG/CODINGTEST_PRACTICE