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Interval List Intersections

MediumP3Coding

Two lists of closed intervals [start, end] are given. Within each list the intervals are disjoint and sorted by start. Return the intersection of the two lists: every non-empty overlap between an interval of the first list and an interval of the second, sorted by start. An overlap of a single point, such as [5,5], counts.

Example 1

Input
firstList = [[0,2],[5,10],[13,23],[24,25]], secondList = [[1,5],[8,12],[15,24],[25,26]]
Output
[[1,2],[5,5],[8,10],[15,23],[24,24],[25,25]]

Example 2

Input
firstList = [[1,3],[5,9]], secondList = []
Output
[]

Constraints

  • 0 <= firstList.length, secondList.length <= 1000
  • 0 <= start <= end <= 10^9
  • Each list is sorted and disjoint (intervals do not even touch).

Hints

Run checks the 3 visible tests, Submit all 9.