Introduction

In this blog post, we will explore how to solve the LeetCode problem "2848" 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 a 0-indexed 2D integer array nums representing the coordinates of the cars parking on a number line. For any index i, nums[i] = [starti, endi] where starti is the starting point of the ith car and endi is the ending point of the ith car. Return the number of integer points on the line that are covered with any part of a car. Example 1: Input: nums = [[3,6],[1,5],[4,7]] Output: 7 Explanation: All the points from 1 to 7 intersect at least one car, therefore the answer would be 7. Example 2: Input: nums = [[1,3],[5,8]] Output: 7 Explanation: Points intersecting at least one car are 1, 2, 3, 5, 6, 7, 8. There are a total of 7 points, therefore the answer would be 7. Constraints: 1 <= nums.length <= 100 nums[i].length == 2 1 <= starti <= endi <= 100

Explanation

Here's the breakdown of the solution:

• Interval Merging: The core idea is to merge overlapping intervals to reduce redundancy in counting covered points.
• Iteration and Counting: Iterate through the merged intervals and calculate the number of covered points within each interval.

• Sorting: Sort the intervals based on their starting points to facilitate the merging process.

• Runtime Complexity: O(n log n) due to sorting. Storage Complexity: O(n) in the worst case to store merged intervals.

Code

    def numberOfPoints(nums):
    """
    Calculates the number of integer points covered by cars parked on a number line.

    Args:
        nums: A list of lists, where each inner list represents a car's start and end position [start, end].

    Returns:
        The total number of covered integer points.
    """

    nums.sort()  # Sort intervals by start points
    merged_intervals = []
    if not nums:
        return 0

    merged_intervals.append(nums[0])

    for i in range(1, len(nums)):
        current_interval = nums[i]
        last_merged_interval = merged_intervals[-1]

        # Check for overlap
        if current_interval[0] <= last_merged_interval[1]:
            # Merge overlapping intervals
            merged_intervals[-1] = [last_merged_interval[0], max(last_merged_interval[1], current_interval[1])]
        else:
            # Add non-overlapping interval
            merged_intervals.append(current_interval)

    total_points = 0
    for interval in merged_intervals:
        total_points += (interval[1] - interval[0] + 1)

    return total_points