Introduction

In this blog post, we will explore how to solve the LeetCode problem "334" 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, return true if there exists a triple of indices (i, j, k) such that i < j < k and nums[i] < nums[j] < nums[k]. If no such indices exists, return false. Example 1: Input: nums = [1,2,3,4,5] Output: true Explanation: Any triplet where i < j < k is valid. Example 2: Input: nums = [5,4,3,2,1] Output: false Explanation: No triplet exists. Example 3: Input: nums = [2,1,5,0,4,6] Output: true Explanation: The triplet (3, 4, 5) is valid because nums[3] == 0 < nums[4] == 4 < nums[5] == 6. Constraints: 1 <= nums.length <= 5 * 105 -231 <= nums[i] <= 231 - 1 Follow up: Could you implement a solution that runs in O(n) time complexity and O(1) space complexity?

Explanation

Here's a breakdown of the optimal solution:

• Maintain two smallest values: Keep track of the smallest element encountered so far (smallest) and the second smallest element encountered so far (second_smallest).
• Iterate and check: Iterate through the array. If the current element is greater than second_smallest, we've found a triplet. If it's smaller than smallest, update smallest. Otherwise, if it's smaller than second_smallest but greater than smallest, update second_smallest.

• Early exit: The algorithm allows for an early exit as soon as a triplet has been identified, therefore optimizing the efficiency of the function.

• Runtime & Storage Complexity: O(n) time complexity, O(1) space complexity.

Code

    def increasingTriplet(nums):
    """
    Given an integer array nums, return true if there exists a triple of indices (i, j, k)
    such that i < j < k and nums[i] < nums[j] < nums[k]. If no such indices exists, return false.

    Args:
        nums (list[int]): An integer array.

    Returns:
        bool: True if there exists a triplet, False otherwise.
    """
    smallest = float('inf')
    second_smallest = float('inf')

    for num in nums:
        if num > second_smallest:
            return True
        elif num < smallest:
            smallest = num
        elif num > smallest and num < second_smallest:
            second_smallest = num

    return False