56-Merge-Intervals.py

'''
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.
'''

class Solution:
    def merge(self, intervals: List[List[int]]) -> List[List[int]]:
        if len(intervals) == 0:
            return []
        sorted_intervals = sorted(intervals, key = lambda x: x[0])
        res = [sorted_intervals[0]]
        for interval in sorted_intervals[1:]:
            if interval[0] <= res[-1][1]:
                res[-1][1] = max(interval[1], res[-1][1])
            else:
                res.append(interval)
        return res