Current section
5 Versions
Jump to
Current section
5 Versions
Compare versions
6
files changed
+31
additions
-629
deletions
| @@ -5,10 +5,27 @@ A sorted set library for Elixir. Implements the | |
| 5 5 | ## Installation |
| 6 6 | |
| 7 7 | Add the following to `deps` section of your `mix.exs`: |
| 8 | - `{:sorted_set, "~> 0.1"}` |
| 8 | + `{:sorted_set, "~> 1.0"}` |
| 9 9 | |
| 10 10 | and then `mix deps.get`. That's it! |
| 11 11 | |
| 12 | - Generate the documentations with `mix docs`. |
| 12 | + Generate the documentation with `mix docs`. |
| 13 | + |
| 14 | + ## About |
| 15 | + |
| 16 | + Sorted sets are backed by a [red-black tree](http://en.wikipedia.org/wiki/Red%E2%80%93black_tree), providing lookup in O(log(n)). Size is tracked automatically, resulting in O(1) |
| 17 | + performance. |
| 13 18 | |
| 14 19 | |
| 20 | + ## Basic Usage |
| 21 | + |
| 22 | + `SortedSet` implements the `Set` behaviour, `Enumerable`, and `Collectable`. |
| 23 | + |
| 24 | + ```elixir |
| 25 | + SortedSet.new() |
| 26 | + |> Set.put(5) |
| 27 | + |> Set.put(1) |
| 28 | + |> Set.put(3) |
| 29 | + |> Enum.reduce([], fn (element, acc) -> [element*2|acc] end) |
| 30 | + # [2, 6, 10] |
| 31 | + ``` |
| @@ -4,11 +4,14 @@ | |
| 4 4 | {<<"description">>,<<"SortedSet implementation for Elixir">>}. |
| 5 5 | {<<"elixir">>,<<"~> 1.0">>}. |
| 6 6 | {<<"files">>, |
| 7 | - [<<"lib/red_black_tree.ex">>,<<"lib/red_black_tree/node.ex">>, |
| 8 | - <<"lib/sorted_set.ex">>,<<"mix.exs">>,<<"README.md">>,<<"LICENSE">>]}. |
| 7 | + [<<"lib/sorted_set.ex">>,<<"mix.exs">>,<<"README.md">>,<<"LICENSE">>]}. |
| 9 8 | {<<"licenses">>,[<<"MIT">>]}. |
| 10 9 | {<<"links">>, |
| 11 10 | [{<<"GitHub">>,<<"https://github.com/SenecaSystems/sorted_set">>}]}. |
| 12 11 | {<<"name">>,<<"sorted_set">>}. |
| 13 | - {<<"requirements">>,[]}. |
| 14 | - {<<"version">>,<<"0.2.0">>}. |
| 12 | + {<<"requirements">>, |
| 13 | + [{<<"red_black_tree">>, |
| 14 | + [{<<"app">>,<<"red_black_tree">>}, |
| 15 | + {<<"optional">>,nil}, |
| 16 | + {<<"requirement">>,<<"~> 1.0">>}]}]}. |
| 17 | + {<<"version">>,<<"1.0.0">>}. |
| @@ -1,606 +0,0 @@ | |
| 1 | - defmodule RedBlackTree do |
| 2 | - @moduledoc """ |
| 3 | - Red-black trees are key-value stores. |
| 4 | - While not guaranteed to be perfectly balanced, they guarantee O(log(n)) search |
| 5 | - time. |
| 6 | - |
| 7 | - The RedBlackTree module contains an eponymous struct and various useful |
| 8 | - functions. |
| 9 | - |
| 10 | - Nodes know their depth (automatically updated on insert/delete) |
| 11 | - """ |
| 12 | - alias RedBlackTree.Node |
| 13 | - |
| 14 | - defstruct root: nil, size: 0 |
| 15 | - |
| 16 | - @key_hash_bucket 4294967296 |
| 17 | - |
| 18 | - # Inline key hashing |
| 19 | - @compile {:inline, key_less_than?: 2, hash_key: 1, fallback_key_hash: 1} |
| 20 | - |
| 21 | - def new() do |
| 22 | - %RedBlackTree{} |
| 23 | - end |
| 24 | - |
| 25 | - def new(values) when is_list(values) do |
| 26 | - new(%RedBlackTree{}, values) |
| 27 | - end |
| 28 | - |
| 29 | - defp new(tree, []) do |
| 30 | - tree |
| 31 | - end |
| 32 | - |
| 33 | - # Allow initialization with key/value tuples |
| 34 | - defp new(tree, [{key, value}|tail]) do |
| 35 | - new(RedBlackTree.insert(tree, key, value), tail) |
| 36 | - end |
| 37 | - |
| 38 | - # Allow initialization with individual values, in which case they will be both |
| 39 | - # the key and the value |
| 40 | - defp new(tree, [key|tail]) do |
| 41 | - new(RedBlackTree.insert(tree, key, key), tail) |
| 42 | - end |
| 43 | - |
| 44 | - def size(%RedBlackTree{size: size}) do |
| 45 | - size |
| 46 | - end |
| 47 | - |
| 48 | - def put(tree, key, value) do |
| 49 | - insert(tree, key, value) |
| 50 | - end |
| 51 | - |
| 52 | - def insert(%RedBlackTree{root: nil}, key, value) do |
| 53 | - %RedBlackTree{root: Node.new(key, value), size: 1} |
| 54 | - end |
| 55 | - |
| 56 | - def insert(%RedBlackTree{root: root, size: size}=tree, key, value) do |
| 57 | - {nodes_added, new_root} = do_insert(root, key, value, 1) |
| 58 | - %RedBlackTree{ |
| 59 | - tree | |
| 60 | - root: make_node_black(new_root), |
| 61 | - size: size + nodes_added |
| 62 | - } |
| 63 | - end |
| 64 | - |
| 65 | - def delete(%RedBlackTree{root: root, size: size}=tree, key) do |
| 66 | - {nodes_removed, new_root} = do_delete(root, key) |
| 67 | - %RedBlackTree{ |
| 68 | - tree | |
| 69 | - root: new_root, |
| 70 | - size: size - nodes_removed |
| 71 | - } |
| 72 | - end |
| 73 | - |
| 74 | - def fetch(tree, key) do |
| 75 | - search(tree, key) |
| 76 | - end |
| 77 | - |
| 78 | - def search(%RedBlackTree{root: root}, key) do |
| 79 | - do_search(root, key) |
| 80 | - end |
| 81 | - |
| 82 | - defp do_search(nil, _key) do |
| 83 | - nil |
| 84 | - end |
| 85 | - |
| 86 | - defp do_search(%Node{key: node_key, value: value}, search_key) when node_key === search_key do |
| 87 | - value |
| 88 | - end |
| 89 | - |
| 90 | - defp do_search(%Node{key: node_key, left: left}, search_key) when search_key < node_key do |
| 91 | - do_search(left, search_key) |
| 92 | - end |
| 93 | - |
| 94 | - defp do_search(%Node{key: node_key, right: right}, search_key) when search_key > node_key do |
| 95 | - do_search(right, search_key) |
| 96 | - end |
| 97 | - |
| 98 | - # For cases when `insert_key !== node_key` but `insert_key == node_key` (e.g. |
| 99 | - # `1` and `1.0`,) hash the keys to provide consistent ordering. |
| 100 | - defp do_search(%Node{key: node_key, left: left, right: right}, search_key) when search_key == node_key do |
| 101 | - if key_less_than?(search_key, node_key) do |
| 102 | - do_search(left, search_key) |
| 103 | - else |
| 104 | - do_search(right, search_key) |
| 105 | - end |
| 106 | - end |
| 107 | - |
| 108 | - def has_key?(%RedBlackTree{root: root}, key) do |
| 109 | - do_has_key?(root, key) |
| 110 | - end |
| 111 | - |
| 112 | - defp do_has_key?(nil, _key) do |
| 113 | - false |
| 114 | - end |
| 115 | - |
| 116 | - defp do_has_key?(%Node{key: node_key}, search_key) when node_key === search_key do |
| 117 | - true |
| 118 | - end |
| 119 | - |
| 120 | - defp do_has_key?(%Node{key: node_key, left: left}, search_key) when search_key < node_key do |
| 121 | - do_has_key?(left, search_key) |
| 122 | - end |
| 123 | - |
| 124 | - defp do_has_key?(%Node{key: node_key, right: right}, search_key) when search_key > node_key do |
| 125 | - do_has_key?(right, search_key) |
| 126 | - end |
| 127 | - |
| 128 | - # For cases when `insert_key !== node_key` but `insert_key == node_key` (e.g. |
| 129 | - # `1` and `1.0`,) hash the keys to provide consistent ordering. |
| 130 | - defp do_has_key?(%Node{key: node_key, left: left, right: right}, search_key) when search_key == node_key do |
| 131 | - if key_less_than?(search_key, node_key) do |
| 132 | - do_has_key?(left, search_key) |
| 133 | - else |
| 134 | - do_has_key?(right, search_key) |
| 135 | - end |
| 136 | - end |
| 137 | - |
| 138 | - |
| 139 | - def balance(%RedBlackTree{root: root}=tree) do |
| 140 | - %RedBlackTree{tree | root: do_balance(root)} |
| 141 | - end |
| 142 | - |
| 143 | - def to_list(%RedBlackTree{}=tree) do |
| 144 | - reduce(tree, [], fn (node, members) -> |
| 145 | - [{node.key, node.value} | members] |
| 146 | - end) |> Enum.reverse |
| 147 | - end |
| 148 | - |
| 149 | - @doc """ |
| 150 | - For each node, calls the provided function passing in (node, acc) |
| 151 | - Optionally takes an order as the first argument which can be one of |
| 152 | - `:in_order`, `:pre_order`, or `:post_order`. |
| 153 | - |
| 154 | - Defaults to `:in_order` if no order is given. |
| 155 | - """ |
| 156 | - def reduce(tree, acc, fun) do |
| 157 | - reduce(:in_order, tree, acc, fun) |
| 158 | - end |
| 159 | - |
| 160 | - def reduce(_order, %RedBlackTree{root: nil}, acc, _fun) do |
| 161 | - acc |
| 162 | - end |
| 163 | - |
| 164 | - def reduce(order, %RedBlackTree{root: root}, acc, fun) do |
| 165 | - do_reduce(order, root, acc, fun) |
| 166 | - end |
| 167 | - |
| 168 | - ## Helpers |
| 169 | - |
| 170 | - defp make_node_black(%Node{}=node) do |
| 171 | - %Node{node | color: :black} |
| 172 | - end |
| 173 | - |
| 174 | - # ¡This is only used as a tiebreaker! |
| 175 | - # For cases when `insert_key !== node_key` but `insert_key == node_key` (e.g. |
| 176 | - # `1` and `1.0`,) hash the keys to provide consistent ordering. |
| 177 | - defp hash_key(key) do |
| 178 | - :erlang.phash2(key, @key_hash_bucket) |
| 179 | - end |
| 180 | - |
| 181 | - # In the case that `hash_key(key1) == hash_key(key2)` we can fall back again |
| 182 | - # to the slower phash function distributed over @key_hash_bucket integers. |
| 183 | - # If these two collide, go home. |
| 184 | - defp fallback_key_hash(key) do |
| 185 | - :erlang.phash(key, @key_hash_bucket) |
| 186 | - end |
| 187 | - |
| 188 | - # Should only be used when `key1 !== key2 and key1 == key2`. In the case |
| 189 | - defp key_less_than?(key1, key2) do |
| 190 | - hashed_key1 = hash_key(key1) |
| 191 | - hashed_key2 = hash_key(key2) |
| 192 | - cond do |
| 193 | - hashed_key1 === hashed_key2 -> |
| 194 | - fallback_key_hash(key1) < fallback_key_hash(key2) |
| 195 | - hashed_key1 < hashed_key2 -> true |
| 196 | - true -> false |
| 197 | - end |
| 198 | - end |
| 199 | - |
| 200 | - ### Operations |
| 201 | - |
| 202 | - #### Insert |
| 203 | - |
| 204 | - defp do_insert(nil, insert_key, insert_value, depth) do |
| 205 | - { |
| 206 | - 1, |
| 207 | - %Node{ |
| 208 | - Node.new(insert_key, insert_value, depth) | |
| 209 | - color: :red |
| 210 | - } |
| 211 | - } |
| 212 | - |
| 213 | - end |
| 214 | - |
| 215 | - defp do_insert(%Node{key: node_key}=node, insert_key, insert_value, _depth) when node_key === insert_key do |
| 216 | - {0, %Node{node | value: insert_value}} |
| 217 | - end |
| 218 | - |
| 219 | - defp do_insert(%Node{key: node_key}=node, insert_key, insert_value, depth) when insert_key < node_key do |
| 220 | - do_insert_left(node, insert_key, insert_value, depth) |
| 221 | - end |
| 222 | - |
| 223 | - defp do_insert(%Node{key: node_key}=node, insert_key, insert_value, depth) when insert_key > node_key do |
| 224 | - do_insert_right(node, insert_key, insert_value, depth) |
| 225 | - end |
| 226 | - |
| 227 | - # For cases when `insert_key !== node_key` but `insert_key == node_key` (e.g. |
| 228 | - # `1` and `1.0`,) hash the keys to provide consistent ordering. |
| 229 | - defp do_insert(%Node{key: node_key}=node, insert_key, insert_value, depth) when insert_key == node_key do |
| 230 | - if key_less_than?(insert_key, node_key) do |
| 231 | - do_insert_left(node, insert_key, insert_value, depth) |
| 232 | - else |
| 233 | - do_insert_right(node, insert_key, insert_value, depth) |
| 234 | - end |
| 235 | - end |
| 236 | - |
| 237 | - defp do_insert_left(%Node{left: left}=node, insert_key, insert_value, depth) do |
| 238 | - {nodes_added, new_left} = do_insert(left, insert_key, insert_value, depth + 1) |
| 239 | - {nodes_added, %Node{node | left: do_balance(new_left)}} |
| 240 | - end |
| 241 | - |
| 242 | - defp do_insert_right(%Node{right: right}=node, insert_key, insert_value, depth) do |
| 243 | - {nodes_added, new_right} = do_insert(right, insert_key, insert_value, depth + 1) |
| 244 | - {nodes_added, %Node{node | right: do_balance(new_right)}} |
| 245 | - end |
| 246 | - |
| 247 | - #### Delete |
| 248 | - |
| 249 | - # If we reach a leaf and the key never matched, do nothing |
| 250 | - defp do_delete(nil, _key) do |
| 251 | - {0, nil} |
| 252 | - end |
| 253 | - |
| 254 | - # If both the right and left are nil, the new tree is nil. For example, |
| 255 | - # deleting A in the following tree results in B having no left |
| 256 | - # |
| 257 | - # B |
| 258 | - # / \ |
| 259 | - # A C |
| 260 | - # |
| 261 | - defp do_delete(%Node{key: node_key, left: nil, right: nil}, delete_key) when node_key === delete_key do |
| 262 | - {1, nil} |
| 263 | - end |
| 264 | - |
| 265 | - # If left is nil and there is a right, promote the right. For example, |
| 266 | - # deleting C in the following tree results in B's right becoming D |
| 267 | - # |
| 268 | - # B |
| 269 | - # / \ |
| 270 | - # A C |
| 271 | - # \ |
| 272 | - # D |
| 273 | - # |
| 274 | - defp do_delete(%Node{key: node_key, left: nil, right: right}, delete_key) when node_key === delete_key do |
| 275 | - {1, %Node{right | depth: right.depth - 1}} |
| 276 | - end |
| 277 | - |
| 278 | - # If there is a left promote it. For example, |
| 279 | - # deleting B in the following tree results in C's left becoming A |
| 280 | - # |
| 281 | - # C |
| 282 | - # / \ |
| 283 | - # B D |
| 284 | - # / |
| 285 | - # A |
| 286 | - # |
| 287 | - defp do_delete(%Node{key: node_key, left: left, right: nil}, delete_key) when node_key === delete_key do |
| 288 | - {1, %Node{left | depth: left.depth - 1}} |
| 289 | - end |
| 290 | - |
| 291 | - # If there are both left and right nodes, recursively promote the left-most |
| 292 | - # nodes. For example, deleting E below results in the following: |
| 293 | - # |
| 294 | - # G => G |
| 295 | - # / \ / \ |
| 296 | - # E H => C H |
| 297 | - # / \ / \ |
| 298 | - # C F => B D |
| 299 | - # / \ / \ |
| 300 | - # A D => A F |
| 301 | - # \ |
| 302 | - # B |
| 303 | - # |
| 304 | - # |
| 305 | - defp do_delete(%Node{key: node_key, left: left, right: right}, delete_key) when node_key === delete_key do |
| 306 | - { |
| 307 | - 1, |
| 308 | - do_balance(%Node{ |
| 309 | - left | |
| 310 | - depth: left.depth - 1, |
| 311 | - left: do_balance(promote(left)), |
| 312 | - right: right |
| 313 | - }) |
| 314 | - } |
| 315 | - end |
| 316 | - |
| 317 | - defp do_delete(%Node{key: node_key}=node, delete_key) when delete_key < node_key do |
| 318 | - do_delete_left(node, delete_key) |
| 319 | - end |
| 320 | - |
| 321 | - defp do_delete(%Node{key: node_key}=node, delete_key) when delete_key > node_key do |
| 322 | - do_delete_right(node, delete_key) |
| 323 | - end |
| 324 | - |
| 325 | - # For cases when `delete_key !== node_key` but `delete_key == node_key` (e.g. |
| 326 | - # `1` and `1.0`,) hash the keys to provide consistent ordering. |
| 327 | - defp do_delete(%Node{key: node_key}=node, delete_key) when delete_key == node_key do |
| 328 | - if key_less_than?(delete_key, node_key) do |
| 329 | - do_delete_left(node, delete_key) |
| 330 | - else |
| 331 | - do_delete_right(node, delete_key) |
| 332 | - end |
| 333 | - end |
| 334 | - |
| 335 | - defp do_delete_left(%Node{left: left}=node, delete_key) do |
| 336 | - {nodes_removed, new_left} = do_delete(left, delete_key) |
| 337 | - { |
| 338 | - nodes_removed, |
| 339 | - %Node{ |
| 340 | - node | |
| 341 | - left: do_balance(new_left) |
| 342 | - } |
| 343 | - } |
| 344 | - end |
| 345 | - |
| 346 | - defp do_delete_right(%Node{right: right}=node, delete_key) do |
| 347 | - {nodes_removed, new_right} = do_delete(right, delete_key) |
| 348 | - { |
| 349 | - nodes_removed, |
| 350 | - %Node{ |
| 351 | - node | |
| 352 | - right: do_balance(new_right) |
| 353 | - } |
| 354 | - } |
| 355 | - end |
| 356 | - |
| 357 | - defp promote(nil) do |
| 358 | - nil |
| 359 | - end |
| 360 | - |
| 361 | - defp promote(%Node{left: nil, right: nil, depth: depth}=node) do |
| 362 | - %Node{ node | color: :red, depth: depth - 1 } |
| 363 | - end |
| 364 | - |
| 365 | - defp promote(%Node{left: left, right: nil, depth: depth}) do |
| 366 | - %Node{ left | color: :red, depth: depth - 1} |
| 367 | - end |
| 368 | - |
| 369 | - defp promote(%Node{left: nil, right: right, depth: depth}) do |
| 370 | - %Node{ right | color: :red, depth: depth - 1} |
| 371 | - end |
| 372 | - |
| 373 | - defp promote(%Node{left: left, right: right, depth: depth}) do |
| 374 | - balance(%Node{ |
| 375 | - left | |
| 376 | - depth: depth - 1, |
| 377 | - left: do_balance(promote(left)), |
| 378 | - right: right |
| 379 | - }) |
| 380 | - end |
| 381 | - |
| 382 | - #### Balance |
| 383 | - |
| 384 | - # If we have a tree that looks like this: |
| 385 | - # B (Black) |
| 386 | - # / \ |
| 387 | - # A D (Red) |
| 388 | - # / \ |
| 389 | - # C F (Red) |
| 390 | - # / \ |
| 391 | - # E G |
| 392 | - # |
| 393 | - # |
| 394 | - # Rotate to balance and look like this: |
| 395 | - # |
| 396 | - # D (Red) |
| 397 | - # / \ |
| 398 | - # B (Black) F (Black) |
| 399 | - # / \ / \ |
| 400 | - # A C E G |
| 401 | - # |
| 402 | - # |
| 403 | - defp do_balance( |
| 404 | - %Node{ |
| 405 | - color: :black, |
| 406 | - left: a_node, |
| 407 | - right: %Node{ |
| 408 | - color: :red, |
| 409 | - left: c_node, |
| 410 | - right: %Node{ |
| 411 | - color: :red, |
| 412 | - left: e_node, |
| 413 | - right: g_node |
| 414 | - }=f_node |
| 415 | - }=d_node |
| 416 | - }=b_node) do |
| 417 | - |
| 418 | - balanced_tree(a_node, b_node, c_node, d_node, e_node, f_node, g_node) |
| 419 | - end |
| 420 | - |
| 421 | - # If we have a tree that looks like this: |
| 422 | - # |
| 423 | - # B (Black) |
| 424 | - # / \ |
| 425 | - # A F (Red) |
| 426 | - # / \ |
| 427 | - # D (Red) G |
| 428 | - # / \ |
| 429 | - # C E |
| 430 | - # |
| 431 | - # Rotate to balance like so: |
| 432 | - # |
| 433 | - # D (Red) |
| 434 | - # / \ |
| 435 | - # B (Black) F (Black) |
| 436 | - # / \ / \ |
| 437 | - # A C E G |
| 438 | - # |
| 439 | - # |
| 440 | - # |
| 441 | - defp do_balance( |
| 442 | - %Node{ |
| 443 | - color: :black, |
| 444 | - left: a_node, |
| 445 | - right: %Node{ |
| 446 | - color: :red, |
| 447 | - left: %Node{ |
| 448 | - color: :red, |
| 449 | - left: c_node, |
| 450 | - right: e_node |
| 451 | - }=d_node, |
| 452 | - right: g_node |
| 453 | - }=f_node |
| 454 | - }=b_node) do |
| 455 | - |
| 456 | - balanced_tree(a_node, b_node, c_node, d_node, e_node, f_node, g_node) |
| 457 | - end |
| 458 | - |
| 459 | - # If we have a tree that looks like this: |
| 460 | - # |
| 461 | - # |
| 462 | - # F (Black) |
| 463 | - # / \ |
| 464 | - # D (Red) G |
| 465 | - # / \ |
| 466 | - # B (Red) E |
| 467 | - # / \ |
| 468 | - # A C |
| 469 | - # |
| 470 | - # |
| 471 | - # Rebalance to look like so: |
| 472 | - # |
| 473 | - # D (Red) |
| 474 | - # / \ |
| 475 | - # B (Black) F (Black) |
| 476 | - # / \ / \ |
| 477 | - # A C E G |
| 478 | - # |
| 479 | - defp do_balance(%Node{ |
| 480 | - color: :black, |
| 481 | - left: %Node{ |
| 482 | - color: :red, |
| 483 | - left: %Node{ |
| 484 | - color: :red, |
| 485 | - left: a_node, |
| 486 | - right: c_node |
| 487 | - }=b_node, |
| 488 | - right: e_node |
| 489 | - }=d_node, |
| 490 | - right: g_node |
| 491 | - }=f_node) do |
| 492 | - |
| 493 | - balanced_tree(a_node, b_node, c_node, d_node, e_node, f_node, g_node) |
| 494 | - end |
| 495 | - |
| 496 | - # If we have a tree that looks like this: |
| 497 | - # |
| 498 | - # F (Black) |
| 499 | - # / \ |
| 500 | - # B (Red) G |
| 501 | - # / \ |
| 502 | - # A D (Red) |
| 503 | - # / \ |
| 504 | - # C E |
| 505 | - # |
| 506 | - # Rebalance to look like this: |
| 507 | - # |
| 508 | - # D (Red) |
| 509 | - # / \ |
| 510 | - # B (Black) F (Black) |
| 511 | - # / \ / \ |
| 512 | - # A C E G |
| 513 | - # |
| 514 | - defp do_balance(%Node{ |
| 515 | - color: :black, |
| 516 | - left: %Node{ |
| 517 | - color: :red, |
| 518 | - left: a_node, |
| 519 | - right: %Node{ |
| 520 | - color: :red, |
| 521 | - left: c_node, |
| 522 | - right: e_node |
| 523 | - }=d_node |
| 524 | - }=b_node, |
| 525 | - right: g_node |
| 526 | - }=f_node) do |
| 527 | - |
| 528 | - balanced_tree(a_node, b_node, c_node, d_node, e_node, f_node, g_node) |
| 529 | - end |
| 530 | - |
| 531 | - |
| 532 | - defp do_balance(node) do |
| 533 | - node |
| 534 | - end |
| 535 | - |
| 536 | - defp balanced_tree(a_node, b_node, c_node, d_node, e_node, f_node, g_node) do |
| 537 | - min_depth = min_depth([a_node, b_node, c_node, d_node, e_node, f_node, g_node]) |
| 538 | - %Node { |
| 539 | - d_node | |
| 540 | - color: :red, |
| 541 | - depth: min_depth, |
| 542 | - left: %Node{b_node | color: :black, depth: min_depth + 1, |
| 543 | - left: %Node{a_node | depth: min_depth + 2}, |
| 544 | - right: %Node{c_node | depth: min_depth + 2}}, |
| 545 | - right: %Node{f_node | color: :black, depth: min_depth + 1, |
| 546 | - left: %Node{e_node | depth: min_depth + 2}, |
| 547 | - right: %Node{g_node | depth: min_depth + 2},} |
| 548 | - } |
| 549 | - end |
| 550 | - |
| 551 | - defp min_depth(list_of_nodes) do |
| 552 | - Enum.reduce(list_of_nodes, -1, fn (node, acc) -> |
| 553 | - if acc == -1 || node.depth < acc do |
| 554 | - node.depth |
| 555 | - else |
| 556 | - acc |
| 557 | - end |
| 558 | - end) |
| 559 | - end |
| 560 | - |
| 561 | - defp do_reduce(_order, nil, acc, _fun) do |
| 562 | - acc |
| 563 | - end |
| 564 | - |
| 565 | - # self, left, right |
| 566 | - defp do_reduce(:pre_order, %Node{left: left, right: right}=node, acc, fun) do |
| 567 | - acc_after_self = fun.(node, acc) |
| 568 | - acc_after_left = do_reduce(:pre_order, left, acc_after_self, fun) |
| 569 | - do_reduce(:pre_order, right, acc_after_left, fun) |
| 570 | - end |
| 571 | - |
| 572 | - # left, self, right |
| 573 | - defp do_reduce(:in_order, %Node{left: left, right: right}=node, acc, fun) do |
| 574 | - acc_after_left = do_reduce(:in_order, left, acc, fun) |
| 575 | - acc_after_self = fun.(node, acc_after_left) |
| 576 | - do_reduce(:in_order, right, acc_after_self, fun) |
| 577 | - end |
| 578 | - |
| 579 | - # left, right, self |
| 580 | - defp do_reduce(:post_order, %Node{left: left, right: right}=node, acc, fun) do |
| 581 | - acc_after_left = do_reduce(:post_order, left, acc, fun) |
| 582 | - acc_after_right = do_reduce(:post_order, right, acc_after_left, fun) |
| 583 | - fun.(node, acc_after_right) |
| 584 | - end |
| 585 | - end |
| 586 | - |
| 587 | - defimpl Access, for: RedBlackTree do |
| 588 | - def get(tree, key) do |
| 589 | - RedBlackTree.search(tree, key) |
| 590 | - end |
| 591 | - |
| 592 | - def get_and_update(tree, key, fun) do |
| 593 | - {get, update} = fun.(RedBlackTree.search(tree, key)) |
| 594 | - {get, RedBlackTree.insert(tree, key, update)} |
| 595 | - end |
| 596 | - end |
| 597 | - |
| 598 | - defimpl Collectable, for: RedBlackTree do |
| 599 | - def into(original) do |
| 600 | - {original, fn |
| 601 | - tree, {:cont, {key, value}} -> RedBlackTree.insert(tree, key, value) |
| 602 | - tree, :done -> tree |
| 603 | - _, :halt -> :ok |
| 604 | - end} |
| 605 | - end |
| 606 | - end |
| @@ -1,14 +0,0 @@ | |
| 1 | - defmodule RedBlackTree.Node do |
| 2 | - defstruct( |
| 3 | - color: :black, |
| 4 | - depth: 1, |
| 5 | - key: nil, |
| 6 | - value: nil, |
| 7 | - left: nil, |
| 8 | - right: nil |
| 9 | - ) |
| 10 | - |
| 11 | - def new(key, value, depth \\ 1) do |
| 12 | - %__MODULE__{key: key, value: value, depth: depth} |
| 13 | - end |
| 14 | - end |
| @@ -54,8 +54,9 @@ defmodule SortedSet do | |
| 54 54 | [1,3,5] |
| 55 55 | """ |
| 56 56 | def to_list(%SortedSet{members: members}) do |
| 57 | - RedBlackTree.to_list(members) |
| 58 | - |> Enum.map(fn ({key, _value}) -> key end) |
| 57 | + Enum.reduce(members, [], fn ({key, _value}, acc) -> |
| 58 | + [key | acc] |
| 59 | + end) |> Enum.reverse |
| 59 60 | end |
| 60 61 | |
| 61 62 | @doc ~S""" |
Loading more files…