1229 - Meeting Scheduler

Mix.install([])

ExUnit.start(auto_run: false)

Solution

https://leetcode.com/problems/meeting-scheduler

defmodule Solution do
  @spec min_available_duration(slots1 :: [[integer]], slots2 :: [[integer]], duration :: integer) ::
          [integer]
  def min_available_duration(slots1, slots2, duration) do
    do_min_available_duration(sort_slots(slots1), sort_slots(slots2), duration)
  end

  defp sort_slots(slots) do
    Enum.sort(slots)
  end

  defp do_min_available_duration(_slots1 = [], _slots2, _duration), do: []
  defp do_min_available_duration(_slots1, _slots2 = [], _duration), do: []

  defp do_min_available_duration(
         slots1 = [s1 | slots1_rest],
         slots2 = [s2 | slots2_rest],
         duration
       ) do
    [s1_start, s1_end] = s1
    [s2_start, s2_end] = s2

    cond do
      s1_end <= s2_start ->
        do_min_available_duration(slots1_rest, slots2, duration)

      s1_start >= s2_end ->
        do_min_available_duration(slots1, slots2_rest, duration)

      true ->
        s_start = max(s1_start, s2_start)
        s_end = min(s1_end, s2_end)

        cond do
          s_end - s_start >= duration ->
            [s_start, s_start + duration]

          s1_start < s2_start and s1_end < s2_end ->
            do_min_available_duration(slots1_rest, slots2, duration)

          s1_start < s2_start and s1_end > s2_end ->
            do_min_available_duration(slots1, slots2_rest, duration)

          s2_start < s1_start and s2_end > s1_end ->
            do_min_available_duration(slots1_rest, slots2, duration)

          s1_start > s2_start ->
            do_min_available_duration(slots1, slots2_rest, duration)

          true ->
            do_min_available_duration(slots1_rest, slots2_rest, duration)
        end
    end
  end
end

defmodule TestSolution do
  use ExUnit.Case, async: false

  test "1" do
    assert Solution.min_available_duration(
             [[10, 50], [60, 120], [140, 210]],
             [[0, 15], [60, 70]],
             8
           ) == [60, 68]
  end

  test "2" do
    assert Solution.min_available_duration(
             [[10, 50], [60, 120], [140, 210]],
             [[0, 15], [60, 70]],
             12
           ) == []
  end

  test "3" do
    assert Solution.min_available_duration(
             [[10, 60]],
             [[12, 17], [21, 50]],
             8
           ) == [21, 29]
  end

  test "4" do
    assert Solution.min_available_duration(
             [[10, 12], [15, 25]],
             [[0, 100]],
             8
           ) == [15, 23]
  end

  test "5" do
    assert Solution.min_available_duration(
             [
               [216_397_070, 363_167_701],
               [98_730_764, 158_208_909],
               [441_003_187, 466_254_040],
               [558_239_978, 678_368_334],
               [683_942_980, 717_766_451]
             ],
             [
               [50_490_609, 222_653_186],
               [512_711_631, 670_791_418],
               [730_229_023, 802_410_205],
               [812_553_104, 891_266_775],
               [230_032_010, 399_152_578]
             ],
             456_085
           ) == [98_730_764, 99_186_849]
  end
end

ExUnit.run()