Guess Number Higher or Lower

Problem

In this game, a number is picked between 1 and n.
You must guess the number using the API guess(num).

The API returns:

-1 → your guess is higher
1 → your guess is lower
0 → your guess is correct

Your task is to find the picked number.

Example

Input
n = 10
pick = 6

Output
6

Approach

We can use Binary Search:
Start with low = 1 and high = n
Find middle value
Check the result using guess(mid)
Adjust search range until the correct number is found

Python Code

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:       # Correct guess
            return mid
        elif res < 0:      # Guess is higher than the pick
            high = mid - 1
        else:              # Guess is lower than the pick
            low = mid + 1

Output
6