Introduction

In this blog post, we will explore how to solve the LeetCode problem "1985" 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

You are given an array of strings nums and an integer k. Each string in nums represents an integer without leading zeros. Return the string that represents the kth largest integer in nums. Note: Duplicate numbers should be counted distinctly. For example, if nums is ["1","2","2"], "2" is the first largest integer, "2" is the second-largest integer, and "1" is the third-largest integer. Example 1: Input: nums = ["3","6","7","10"], k = 4 Output: "3" Explanation: The numbers in nums sorted in non-decreasing order are ["3","6","7","10"]. The 4th largest integer in nums is "3". Example 2: Input: nums = ["2","21","12","1"], k = 3 Output: "2" Explanation: The numbers in nums sorted in non-decreasing order are ["1","2","12","21"]. The 3rd largest integer in nums is "2". Example 3: Input: nums = ["0","0"], k = 2 Output: "0" Explanation: The numbers in nums sorted in non-decreasing order are ["0","0"]. The 2nd largest integer in nums is "0". Constraints: 1 <= k <= nums.length <= 104 1 <= nums[i].length <= 100 nums[i] consists of only digits. nums[i] will not have any leading zeros.

Explanation

Here's the solution:

• Use a min-heap (priority queue) to keep track of the k largest numbers seen so far.
• Iterate through the input array nums. For each number, compare it with the smallest element in the min-heap. If the current number is larger, replace the smallest element in the heap with the current number.

• After iterating through all numbers, the smallest element in the min-heap (root) will be the kth largest number.

• Time Complexity: O(N log k), where N is the number of strings in nums. Space Complexity: O(k) to store the min-heap.

Code

    import heapq

def kthLargestNumber(nums, k):
    """
    Finds the kth largest number in an array of strings representing integers.

    Args:
        nums: A list of strings, where each string represents an integer.
        k: An integer representing the desired kth largest number.

    Returns:
        A string representing the kth largest number in nums.
    """

    min_heap = []
    for num_str in nums:
        num = int(num_str)
        if len(min_heap) < k:
            heapq.heappush(min_heap, num)
        elif num > min_heap[0]:
            heapq.heapreplace(min_heap, num)  # Efficiently replace and heapify

    return str(min_heap[0])