Introduction

In this blog post, we will explore how to solve the LeetCode problem "374" using AI. LeetCode is a popular platform for preparing for coding interviews, and with the help of AI tools like Chatmagic, we can generate solutions quickly and efficiently - helping you pass the interviews and get the job offer without having to study for months.

Problem Statement

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 three possible results: -1: Your guess is higher than the number I picked (i.e. num > pick). 1: Your guess is lower than the number I picked (i.e. num < pick). 0: your guess is equal to the number I picked (i.e. num == pick). 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 Constraints: 1 <= n <= 231 - 1 1 <= pick <= n

Explanation

Here's an efficient solution to the Guess Game problem:

• Binary Search: The core idea is to use binary search to efficiently narrow down the search range. We repeatedly halve the interval until we find the correct number.

• Adjust Search Range: Based on the result of the guess() API, we adjust the search range. If the guess is too high, we reduce the upper bound. If it's too low, we increase the lower bound.

• Runtime & Storage Complexity: O(log n) runtime, O(1) storage.

Code

    def guessNumber(n: int) -> int:
    """
    Implements the Guess Game using binary search.

    Args:
        n: The upper bound of the range of numbers to guess from (1 to n).

    Returns:
        The number that was picked.
    """
    low = 1
    high = n

    while low <= high:
        mid = low + (high - low) // 2  # Prevent potential overflow
        result = guess(mid)

        if result == 0:
            return mid
        elif result == -1:
            high = mid - 1
        else:
            low = mid + 1

    return -1  # Should not reach here based on problem constraints

# Dummy guess function for local testing, to be replaced with the actual API call
def guess(num: int) -> int:
    pick = 6 # Replace with your 'pick' value for local testing
    if num > pick:
        return -1
    elif num < pick:
        return 1
    else:
        return 0