56 Merge Intervals

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.

Constraints:

• 1 <= intervals.length <= 104
• intervals[i].length == 2
• 0 <= starti <= endi <= 104

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class Solution:
    def merge(self, intervals: List[List[int]]) -> List[List[int]]:
        sorted_intervals = sorted(intervals, key=lambda x: x[0])
        res = []
        start, end = sorted_intervals[0]
        for i_start, i_end in sorted_intervals:
            if i_start <= end:
                end = max(end, i_end)
            else:
                res.append([start, end])
                start, end = i_start, i_end
        res.append([start, end])
        return res