commit 987d2410ff43ac4e798aa539fbf67474bf955bf0 · hauleth.dev/advent-of-code

+218
2024/day10.livemd
···

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

     

       2
       2
       +
       

     

       3
       3
       +
       # Day 10

     

       4
       4
       +
       

     

       5
       5
       +
       ```elixir

     

       6
       6
       +
       Mix.install([:kino_aoc])

     

       7
       7
       +
       ```

     

       8
       8
       +
       

     

       9
       9
       +
       ## Section

     

       10
       10
       +
       

     

       11
       11
       +
       <!-- livebook:{"attrs":"eyJhc3NpZ25fdG8iOiJwdXp6bGVfaW5wdXQiLCJkYXkiOiIxMCIsInNlc3Npb25fc2VjcmV0IjoiQURWRU5UX09GX0NPREVfU0VTU0lPTiIsInllYXIiOiIyMDI0In0","chunks":null,"kind":"Elixir.KinoAOC.HelperCell","livebook_object":"smart_cell"} -->

     

       12
       12
       +
       

     

       13
       13
       +
       ```elixir

     

       14
       14
       +
       {:ok, puzzle_input} =

     

       15
       15
       +
         KinoAOC.download_puzzle("2024", "10", System.fetch_env!("LB_ADVENT_OF_CODE_SESSION"))

     

       16
       16
       +
       ```

     

       17
       17
       +
       

     

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

     

       19
       19
       +
       

     

       20
       20
       +
       ```

     

       21
       21
       +
       {:ok,

     

       22
       22
       +
        "543067650323210321032110356789890110710189878760134567\n612148941212306782345091235410765227893258759651021298\n701238932301456798106787549323454336794567549842330807\n898547215450589867287654678892961245987654456732498910\n987656306769678956398013234781870301256003301201567821\n234543215878760145478920105690210982340112210341056932\n109650124981232230569834124567345673451234985452347845\n018744323890341021656765033438454589298545676701037796\n199803210787650110765017842129823672107655677812378987\n785012345654789541874326956010510563201234389983405676\n174321498723498632903455467173421454102348210234514430\n065430239014323721212762398982567876218959650149623521\n145540128765017890101871081071018967327968743898734678\n236692134984178768718981012567894458456876212798604329\n987783005673269659654108923458763349663212108789015012\n896654012562154546743267830309854218767103419276126787\n765780123473043432890154321212903109878756578125435698\n434099874984012301740125654567812893469017647030165556\n323101065765101787434436763058906732154178736543256765\n013298187890678696325569892143215440043289128954343894\n010367296541549045016678765014300351234567037760012983\n329458305032132134787867410967891267653438546891898012\n458789414145010120196986323898763298344129655432743210\n567076523236678743285898456777654101201098766653658901\n456167654107549658374567689985403100312434985567877014\n343228943298938569843210576876312238920125676656986323\n651014543498127478755765435410278947437876985543235434\n743223672567078369876890324320127656506987234350145632\n894102981089569232125981210451256543215432122341076541\n765091234676352101034674323401237894101341001456789830\n014780365445443032126501012532345743103210112565898321\n123689876034321145098432107645236743254101101876543210\n094545763125210056788943258896107858969010332987674301\n785430432106782169877652349787567967678321245696784561\n876021569045893458965601654343478914565414326781093870\n987109878010432167014298710234323901258905015492012901\n789219894324569052123109620123217892109876012323458692\n654308765543678743013234538994106543010870965410069783\n789877787632189852101110145885287676521961871012178654\n034565896601087601211001406776896789437652676523468743\n121053795542194512389132312345445676548943989430549012\n262342187634765433498545434531230107401232104321678298\n876533014123892324567696526540043298340981010780890187\n983414523016101019876587017832134781256672125690743296\n032101654327892100345678789901295690764543434321652345\n123089789236743981234589654800387789835678987787601336\n854176590187656876104310343211456876544549016098543223\n965765410194545675465231230898565963233432145123210112\n876894321243232980370110141767653210112321039654101101\n146765232100101061289879852632154100203410128789210322\n036787103761267876518768763543069911012543454376325412\n123498654854356987405650654985678892327632567215436701\n210567569983543292314321569876301765438761078904589898\n325456478754330101223433478765432654349652987615678765"}

     

       23
       23
       +
       ```

     

       24
       24
       +
       

     

       25
       25
       +
       ```elixir

     

       26
       26
       +
       map =

     

       27
       27
       +
         for {row, y} <- puzzle_input |> String.split("\n", trim: true) |> Enum.with_index(),

     

       28
       28
       +
             {h, x} <- row |> String.to_charlist() |> Enum.with_index(),

     

       29
       29
       +
             into: %{},

     

       30
       30
       +
             do: {{x, y}, h - ?0}

     

       31
       31
       +
       ```

     

       32
       32
       +
       

     

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

     

       34
       34
       +
       

     

       35
       35
       +
       ```

     

       36
       36
       +
       %{

     

       37
       37
       +
         {37, 47} => 3,

     

       38
       38
       +
         {38, 2} => 4,

     

       39
       39
       +
         {1, 26} => 5,

     

       40
       40
       +
         {32, 15} => 4,

     

       41
       41
       +
         {35, 30} => 3,

     

       42
       42
       +
         {37, 53} => 4,

     

       43
       43
       +
         {4, 5} => 4,

     

       44
       44
       +
         {8, 50} => 3,

     

       45
       45
       +
         {11, 39} => 1,

     

       46
       46
       +
         {22, 38} => 1,

     

       47
       47
       +
         {20, 41} => 8,

     

       48
       48
       +
         {29, 25} => 6,

     

       49
       49
       +
         {29, 26} => 0,

     

       50
       50
       +
         {47, 27} => 0,

     

       51
       51
       +
         {31, 42} => 4,

     

       52
       52
       +
         {9, 34} => 0,

     

       53
       53
       +
         {47, 38} => 2,

     

       54
       54
       +
         {20, 3} => 7,

     

       55
       55
       +
         {47, 44} => 1,

     

       56
       56
       +
         {22, 37} => 3,

     

       57
       57
       +
         {22, 36} => 0,

     

       58
       58
       +
         {45, 7} => 7,

     

       59
       59
       +
         {19, 38} => 0,

     

       60
       60
       +
         {27, 21} => 9,

     

       61
       61
       +
         {9, 33} => 1,

     

       62
       62
       +
         {26, 41} => 4,

     

       63
       63
       +
         {52, 42} => 8,

     

       64
       64
       +
         {21, 35} => 2,

     

       65
       65
       +
         {42, 8} => 6,

     

       66
       66
       +
         {19, 22} => 9,

     

       67
       67
       +
         {16, 10} => 3,

     

       68
       68
       +
         {21, 45} => 5,

     

       69
       69
       +
         {11, 8} => 7,

     

       70
       70
       +
         {26, 21} => 0,

     

       71
       71
       +
         {21, 48} => 1,

     

       72
       72
       +
         {50, 40} => 9,

     

       73
       73
       +
         {10, 25} => 9,

     

       74
       74
       +
         {11, 19} => 0,

     

       75
       75
       +
         {16, 38} => 5,

     

       76
       76
       +
         {35, 15} => 8,

     

       77
       77
       +
         {37, 15} => 6,

     

       78
       78
       +
         {35, 26} => 7,

     

       79
       79
       +
         {28, 20} => 1,

     

       80
       80
       +
         {45, 19} => 9,

     

       81
       81
       +
         {27, 22} => 8,

     

       82
       82
       +
         {16, 24} => 5,

     

       83
       83
       +
         {6, 18} => 0,

     

       84
       84
       +
         {10, 32} => 2,

     

       85
       85
       +
         {32, ...} => 8,

     

       86
       86
       +
         {...} => 7,

     

       87
       87
       +
         ...

     

       88
       88
       +
       }

     

       89
       89
       +
       ```

     

       90
       90
       +
       

     

       91
       91
       +
       ```elixir

     

       92
       92
       +
       starts = Enum.filter(map, fn {_, elev} -> elev == 0 end)

     

       93
       93
       +
       ```

     

       94
       94
       +
       

     

       95
       95
       +
       <!-- livebook:{"output":true} -->

     

       96
       96
       +
       

     

       97
       97
       +
       ```

     

       98
       98
       +
       [

     

       99
       99
       +
         {{38, 5}, 0},

     

       100
       100
       +
         {{24, 7}, 0},

     

       101
       101
       +
         {{11, 35}, 0},

     

       102
       102
       +
         {{3, 9}, 0},

     

       103
       103
       +
         {{15, 36}, 0},

     

       104
       104
       +
         {{41, 32}, 0},

     

       105
       105
       +
         {{51, 14}, 0},

     

       106
       106
       +
         {{51, 24}, 0},

     

       107
       107
       +
         {{5, 12}, 0},

     

       108
       108
       +
         {{4, 35}, 0},

     

       109
       109
       +
         {{40, 4}, 0},

     

       110
       110
       +
         {{46, 4}, 0},

     

       111
       111
       +
         {{22, 30}, 0},

     

       112
       112
       +
         {{27, 12}, 0},

     

       113
       113
       +
         {{7, 4}, 0},

     

       114
       114
       +
         {{24, 43}, 0},

     

       115
       115
       +
         {{31, 20}, 0},

     

       116
       116
       +
         {{29, 42}, 0},

     

       117
       117
       +
         {{29, 9}, 0},

     

       118
       118
       +
         {{10, 2}, 0},

     

       119
       119
       +
         {{0, 20}, 0},

     

       120
       120
       +
         {{15, 20}, 0},

     

       121
       121
       +
         {{14, 0}, 0},

     

       122
       122
       +
         {{42, 48}, 0},

     

       123
       123
       +
         {{40, 15}, 0},

     

       124
       124
       +
         {{43, 14}, 0},

     

       125
       125
       +
         {{19, 2}, 0},

     

       126
       126
       +
         {{14, 22}, 0},

     

       127
       127
       +
         {{34, 35}, 0},

     

       128
       128
       +
         {{38, 42}, 0},

     

       129
       129
       +
         {{23, 5}, 0},

     

       130
       130
       +
         {{0, 11}, 0},

     

       131
       131
       +
         {{44, 11}, 0},

     

       132
       132
       +
         {{15, 30}, 0},

     

       133
       133
       +
         {{17, 44}, 0},

     

       134
       134
       +
         {{31, 32}, 0},

     

       135
       135
       +
         {{48, 28}, 0},

     

       136
       136
       +
         {{21, 39}, 0},

     

       137
       137
       +
         {{49, 13}, 0},

     

       138
       138
       +
         {{29, 45}, 0},

     

       139
       139
       +
         {{4, 37}, 0},

     

       140
       140
       +
         {{53, 31}, 0},

     

       141
       141
       +
         {{45, 46}, 0},

     

       142
       142
       +
         {{43, 29}, 0},

     

       143
       143
       +
         {{8, 0}, 0},

     

       144
       144
       +
         {{47, 42}, 0},

     

       145
       145
       +
         {{7, 14}, 0},

     

       146
       146
       +
         {{52, ...}, 0},

     

       147
       147
       +
         {{...}, ...},

     

       148
       148
       +
         {...},

     

       149
       149
       +
         ...

     

       150
       150
       +
       ]

     

       151
       151
       +
       ```

     

       152
       152
       +
       

     

       153
       153
       +
       ```elixir

     

       154
       154
       +
       defmodule Trail do

     

       155
       155
       +
         def traverse(start, map), do: MapSet.new(traverse(start, map, []))

     

       156
       156
       +
       

     

       157
       157
       +
         defp traverse({curr, 9}, _map, acc), do: [[{curr, 9} | acc]]

     

       158
       158
       +
         defp traverse({curr, elev}, map, acc) do

     

       159
       159
       +
           curr

     

       160
       160
       +
           |> surroundings()

     

       161
       161
       +
           |> then(&Map.take(map, &1))

     

       162
       162
       +
           |> Enum.filter(fn {_, h} -> elev + 1 == h end)

     

       163
       163
       +
           |> Enum.flat_map(&traverse(&1, map, [{curr, elev} | acc]))

     

       164
       164
       +
         end

     

       165
       165
       +
       

     

       166
       166
       +
         defp surroundings({x, y}) do

     

       167
       167
       +
           [

     

       168
       168
       +
             {x, y - 1},

     

       169
       169
       +
             {x - 1, y},

     

       170
       170
       +
             {x, y + 1},

     

       171
       171
       +
             {x + 1, y}

     

       172
       172
       +
           ]

     

       173
       173
       +
         end

     

       174
       174
       +
       end

     

       175
       175
       +
       ```

     

       176
       176
       +
       

     

       177
       177
       +
       <!-- livebook:{"output":true} -->

     

       178
       178
       +
       

     

       179
       179
       +
       ```

     

       180
       180
       +
       {:module, Trail, <<70, 79, 82, 49, 0, 0, 11, ...>>, {:surroundings, 1}}

     

       181
       181
       +
       ```

     

       182
       182
       +
       

     

       183
       183
       +
       ## Part 1

     

       184
       184
       +
       

     

       185
       185
       +
       ```elixir

     

       186
       186
       +
       starts

     

       187
       187
       +
       |> Enum.map(fn start ->

     

       188
       188
       +
         Trail.traverse(start, map)

     

       189
       189
       +
         |> MapSet.new(&hd/1)

     

       190
       190
       +
         |> MapSet.size()

     

       191
       191
       +
       end)

     

       192
       192
       +
       |> Enum.sum()

     

       193
       193
       +
       ```

     

       194
       194
       +
       

     

       195
       195
       +
       <!-- livebook:{"output":true} -->

     

       196
       196
       +
       

     

       197
       197
       +
       ```

     

       198
       198
       +
       733

     

       199
       199
       +
       ```

     

       200
       200
       +
       

     

       201
       201
       +
       ## Section

     

       202
       202
       +
       

     

       203
       203
       +
       ```elixir

     

       204
       204
       +
       starts

     

       205
       205
       +
       |> Enum.map(fn start ->

     

       206
       206
       +
         Trail.traverse(start, map)

     

       207
       207
       +
         |> MapSet.size()

     

       208
       208
       +
       end)

     

       209
       209
       +
       |> Enum.sum()

     

       210
       210
       +
       ```

     

       211
       211
       +
       

     

       212
       212
       +
       <!-- livebook:{"output":true} -->

     

       213
       213
       +
       

     

       214
       214
       +
       ```

     

       215
       215
       +
       1514

     

       216
       216
       +
       ```

     

       217
       217
       +
       

     

       218
       218
       +
       <!-- livebook:{"offset":6605,"stamp":{"token":"XCP.68U6SzidJCV7il26kiMv6z5qLEx_50_v2V7x6LqV9t8LQG1-aShVMNE1DEgCj9SwpKOn02np0aeSu5T1parIYMF9MeWGGfqP-oc4UGnDiDGDtJ5RGqdwcxcPjuPUQmCtZj0","version":2}} -->