Introduction

In this blog post, we will explore how to solve the LeetCode problem "1893" 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 2D integer array ranges and two integers left and right. Each ranges[i] = [starti, endi] represents an inclusive interval between starti and endi. Return true if each integer in the inclusive range [left, right] is covered by at least one interval in ranges. Return false otherwise. An integer x is covered by an interval ranges[i] = [starti, endi] if starti <= x <= endi. Example 1: Input: ranges = [[1,2],[3,4],[5,6]], left = 2, right = 5 Output: true Explanation: Every integer between 2 and 5 is covered: - 2 is covered by the first range. - 3 and 4 are covered by the second range. - 5 is covered by the third range. Example 2: Input: ranges = [[1,10],[10,20]], left = 21, right = 21 Output: false Explanation: 21 is not covered by any range. Constraints: 1 <= ranges.length <= 50 1 <= starti <= endi <= 50 1 <= left <= right <= 50

Explanation

Here's the solution to determine if a given range is covered by a set of intervals, along with an explanation and the Python code:

• High-Level Approach:

  • Create a boolean array (or set) to represent the coverage status of each number within the relevant range (from left to right).
  • Iterate through the ranges array. For each range, mark the numbers within that range as covered in the boolean array/set.
  • Finally, check if all numbers from left to right are marked as covered.

• Complexity:

  • Runtime Complexity: O(n*m), where n is the number of ranges and m is the maximum span of any range (or right - left). Space complexity: O(right - left).

Code

    def isCovered(ranges, left, right):
    """
    Checks if every number in the range [left, right] is covered by at least one interval in ranges.

    Args:
        ranges: A list of lists, where each inner list represents a range [start, end].
        left: The left boundary of the range to check.
        right: The right boundary of the range to check.

    Returns:
        True if every number in [left, right] is covered, False otherwise.
    """

    covered = [False] * (right - left + 1)  # Boolean array to track coverage

    for start, end in ranges:
        for i in range(max(left, start), min(right, end) + 1):
            covered[i - left] = True

    return all(covered)