commit fceb5e95ded061477cc6d013a62222c7ded292e8 · hauleth.dev/advent-of-code

+107

2023/day06.livemd

···

       1
       +
       <!-- livebook:{"persist_outputs":true} -->

     

       2
       +
       

     

       3
       +
       # Day 06

     

       4
       +
       

     

       5
       +
       ```elixir

     

       6
       +
       Mix.install([:kino_aoc])

     

       7
       +
       ```

     

       8
       +
       

     

       9
       +
       ## Section

     

       10
       +
       

     

       11
       +
       <!-- livebook:{"attrs":{"assign_to":"puzzle_input","day":"6","session_secret":"ADVENT_OF_CODE_SESSION","year":"2023"},"chunks":null,"kind":"Elixir.KinoAOC.HelperCell","livebook_object":"smart_cell"} -->

     

       12
       +
       

     

       13
       +
       ```elixir

     

       14
       +
       {:ok, puzzle_input} =

     

       15
       +
         KinoAOC.download_puzzle("2023", "6", System.fetch_env!("LB_ADVENT_OF_CODE_SESSION"))

     

       16
       +
       ```

     

       17
       +
       

     

       18
       +
       <!-- livebook:{"output":true} -->

     

       19
       +
       

     

       20
       +
       ```

     

       21
       +
       {:ok, "Time:        44     80     65     72\nDistance:   208   1581   1050   1102"}

     

       22
       +
       ```

     

       23
       +
       

     

       24
       +
       ```elixir

     

       25
       +
       # puzzle_input =

     

       26
       +
       """

     

       27
       +
       Time:      7  15   30

     

       28
       +
       Distance:  9  40  200

     

       29
       +
       """

     

       30
       +
       |> String.trim()

     

       31
       +
       ```

     

       32
       +
       

     

       33
       +
       <!-- livebook:{"output":true} -->

     

       34
       +
       

     

       35
       +
       ```

     

       36
       +
       "Time:      7  15   30\nDistance:  9  40  200"

     

       37
       +
       ```

     

       38
       +
       

     

       39
       +
       ```elixir

     

       40
       +
       defmodule Day06 do

     

       41
       +
         def solve(t, d) do

     

       42
       +
           delta = t ** 2 - 4 * d

     

       43
       +
       

     

       44
       +
           sq_delta = :math.sqrt(delta)

     

       45
       +
       

     

       46
       +
           diff = if sq_delta == floor(sq_delta), do: 1, else: 0

     

       47
       +
       

     

       48
       +
           x1 = (-t + sq_delta) / -2

     

       49
       +
           x2 = (-t - sq_delta) / -2

     

       50
       +
       

     

       51
       +
           ceil(x2) - ceil(x1) - diff

     

       52
       +
         end

     

       53
       +
       end

     

       54
       +
       ```

     

       55
       +
       

     

       56
       +
       <!-- livebook:{"output":true} -->

     

       57
       +
       

     

       58
       +
       ```

     

       59
       +
       {:module, Day06, <<70, 79, 82, 49, 0, 0, 8, ...>>, {:solve, 2}}

     

       60
       +
       ```

     

       61
       +
       

     

       62
       +
       ## Part 1

     

       63
       +
       

     

       64
       +
       ```elixir

     

       65
       +
       puzzle_input

     

       66
       +
       |> String.split("\n")

     

       67
       +
       |> Enum.map(fn line ->

     

       68
       +
         line

     

       69
       +
         |> String.split(" ", trim: true)

     

       70
       +
         |> tl()

     

       71
       +
         |> Enum.map(&String.to_integer/1)

     

       72
       +
       end)

     

       73
       +
       |> Enum.zip()

     

       74
       +
       |> Enum.map(fn {t, d} -> Day06.solve(t, d) end)

     

       75
       +
       |> Enum.product()

     

       76
       +
       ```

     

       77
       +
       

     

       78
       +
       <!-- livebook:{"output":true} -->

     

       79
       +
       

     

       80
       +
       ```

     

       81
       +
       32076

     

       82
       +
       ```

     

       83
       +
       

     

       84
       +
       ## Part 2

     

       85
       +
       

     

       86
       +
       ```elixir

     

       87
       +
       [t, d] =

     

       88
       +
         puzzle_input

     

       89
       +
         |> String.split("\n")

     

       90
       +
         |> Enum.map(fn line ->

     

       91
       +
           line

     

       92
       +
           |> String.split(" ", trim: true)

     

       93
       +
           |> tl()

     

       94
       +
           |> Enum.join()

     

       95
       +
           |> String.to_integer()

     

       96
       +
         end)

     

       97
       +
       

     

       98
       +
       Day06.solve(t, d)

     

       99
       +
       ```

     

       100
       +
       

     

       101
       +
       <!-- livebook:{"output":true} -->

     

       102
       +
       

     

       103
       +
       ```

     

       104
       +
       34278221

     

       105
       +
       ```

     

       106
       +
       

     

       107
       +
       <!-- livebook:{"offset":1728,"stamp":{"token":"XCP.RVwRJJq0k3Evn9IAmQDOmuVfBQ2xs0pbIqwAVIMLYEO8Olj2RUttefJ6ky9G2BD-EzyDh-ZjERuBL8PVkFPkYz8g7hdsY0keFA-TEIL4GC3n2j_IwPT1JHFDQ0FwiPBw5g","version":2}} -->