Merge Intervals

Problem Statement

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

Leetcode link

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 <= start_i <= end_i <= 10⁴

Code

Python3 Code

class Solution:
    def merge(self, intervals: List[List[int]]) -> List[List[int]]:
        if not intervals:
            return []

        sortedIntervals = sorted(intervals)
        mergedIntervals = []

        currentStart, currentEnd = sortedIntervals[0]

        for start, end in sortedIntervals[1:]:
            if start > currentEnd:
                mergedIntervals.append((currentStart, currentEnd))
                currentStart, currentEnd = start, end
            else:
                currentEnd = max(end, currentEnd)

        mergedIntervals.append((currentStart, currentEnd))

        return mergedIntervals