Introduction

In this blog post, we will explore how to solve the LeetCode problem "628" 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

Given an integer array nums, find three numbers whose product is maximum and return the maximum product. Example 1: Input: nums = [1,2,3] Output: 6 Example 2: Input: nums = [1,2,3,4] Output: 24 Example 3: Input: nums = [-1,-2,-3] Output: -6 Constraints: 3 <= nums.length <= 104 -1000 <= nums[i] <= 1000

Explanation

Here's the breakdown of the solution:

• Identify Key Scenarios: The maximum product can arise from either the product of the three largest numbers or the product of the two smallest (most negative) numbers and the largest positive number.
• Efficiently Find Extremes: Use a linear scan to find the two smallest and the three largest numbers in the array, without fully sorting it, thus optimizing performance.

• Compare Products: Calculate both potential maximum products and return the larger of the two.

• Runtime Complexity: O(n), Storage Complexity: O(1)

Code

    def maximumProduct(nums):
    """
    Finds the maximum product of three numbers in an integer array.

    Args:
        nums: An integer array.

    Returns:
        The maximum product of three numbers in the array.
    """

    min1 = float('inf')
    min2 = float('inf')
    max1 = float('-inf')
    max2 = float('-inf')
    max3 = float('-inf')

    for n in nums:
        if n <= min1:
            min2 = min1
            min1 = n
        elif n <= min2:
            min2 = n

        if n >= max1:
            max3 = max2
            max2 = max1
            max1 = n
        elif n >= max2:
            max3 = max2
            max2 = n
        elif n >= max3:
            max3 = n

    return max(min1 * min2 * max1, max1 * max2 * max3)