"""
56. Merge Intervals
Difficulty: Medium
https://leetcode.com/problems/merge-intervals/

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Given an array of intervals where intervals[i] = [starti, endi],
merge all overlapping intervals, and return an array of the
non-overlapping intervals that cover all the intervals in the input.



Example 1:

Input: intervals = [[1,3],[2,6],[8,10],[15,18]]
Output: [[1,6],[8,10],[15,18]]
Explanation: Since intervals [1,3] and [2,6] overlap, merge them into
[1,6].

Example 2:

Input: intervals = [[1,4],[4,5]]
Output: [[1,5]]
Explanation: Intervals [1,4] and [4,5] are considered overlapping.

Example 3:

Input: intervals = [[4,7],[1,4]]
Output: [[1,7]]
Explanation: Intervals [1,4] and [4,7] are considered overlapping.



Constraints:

        • 1 <= intervals.length <= 10^4

        • intervals[i].length == 2

        • 0 <= starti <= endi <= 10^4
"""


class Solution:
    def merge(self, intervals: list[list[int]]) -> list[list[int]]:
        intervals.sort(key=lambda x: x[0])
        result = []

        for start, end in intervals:
            if result and start <= result[-1][1]:
                result[-1][1] = max(result[-1][1], end)
            else:
                result.append([start, end])

        return result