Insert Interval

You are given an array of non-overlapping intervals intervals where intervals[i] = [starti, endi] represent the start and the end of the ith interval and intervals is sorted in ascending order by starti. You are also given an interval newInterval = [start, end] that represents the start and end of another interval.

Insert newInterval into intervals such that intervals is still sorted in ascending order by starti and intervals still does not have any overlapping intervals (merge overlapping intervals if necessary).

Return intervals after the insertion.

Example 1:

Input: intervals = [[1,3],[6,9]], newInterval = [2,5]
Output: [[1,5],[6,9]]

Example 2:

Input: intervals = [[1,2],[3,5],[6,7],[8,10],[12,16]], newInterval = [4,8]
Output: [[1,2],[3,10],[12,16]]
Explanation: Because the new interval [4,8] overlaps with [3,5],[6,7],[8,10].

Solution

Since the interval is sorted for us, we can filter the intervals into three categories:

Intersecting with the new interval
Before the new interval
After the new interval

If the times are intersecting with the new interval, the new interval widens to the minimum times of both intervals, and the maximum times of both intervals.

class Solution:
    def insert(self, intervals: List[List[int]], newInterval: List[int]) -> List[List[int]]:
        left, right, start, end = [], [], *newInterval

        for interval in intervals:
            if interval[1] < start:
                left.append(interval)
            elif interval[0] > end:
                right.append(interval)
            else:
                start = min(start, interval[0])
                end = max(end, interval[1])

        return left + [[start, end]] + right

Table of Contents

Insert Interval

Solution