Insert Interval

Insert Interval is a Medium Data Structures and Algorithms interview problem you can solve, run and submit on Thita.ai. It belongs to the Greedy Patterns pattern, in the Interval Merging/Scheduling subpattern.

Problem statement

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.

Note that you don't need to modify intervals in-place. You can make a new array and return it.

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].

Constraints:

- 0 <= intervals.length <= 104

- intervals[i].length == 2

- 0 <= starti <= endi <= 105

- intervals is sorted by starti in ascending order.

- newInterval.length == 2

- 0 <= start <= end <= 105

Topics and companies

Topics: Array.

Reported in interviews at Google, Twitter, Amazon, Apple, Facebook, Microsoft.

How to practise Insert Interval on Thita.ai

Starter code is provided in C, C#, C++, Go, Java, JavaScript and Python. Your solution runs against 5 test cases for this problem, with the AI coach available for a hint when you are stuck rather than a finished answer. The reference solution runs in O(N), where N is the number of intervals. Each interval is visited at most once. time and O(N), for the result vector that stores the merged intervals. space.

Open Insert Interval in the code editor, or read the Insert Interval editorial for a worked solution with its approach and complexity analysis.

Where Insert Interval sits in the DSA pattern sheet

• Greedy Patterns pattern guide
• Interval Merging/Scheduling subpattern
• The full DSA patterns sheet
• All coding practice problems

Problems related to Insert Interval

Other problems that use the same Interval Merging/Scheduling and Greedy Patterns techniques:

• Divide Intervals Into Minimum Number of Groups — Medium, same subpattern
• Merge Intervals — Medium, same subpattern
• Assign Cookies — Easy, same pattern
• Candy — Hard, same pattern
• Distant Barcodes — Medium, same pattern
• Employee Free Time — Hard, same pattern