Add an Elixir solutions for challenge 267 task 2.

1 files changed, 111 insertions, 0 deletions

diff --git a/challenge-267/packy-anderson/elixir/ch-2.exs b/challenge-267/packy-anderson/elixir/ch-2.exs
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+#!/usr/bin/env elixir
+
+# You are given a string, $str, and a 26-items array @widths
+# containing the width of each character from a to z.
+
+# Write a script to find out the number of lines and the width
+# of the last line needed to display the given string,
+# assuming you can only fit 100 width units on a line.
+
+# Example 1
+# Input: $str = "abcdefghijklmnopqrstuvwxyz"
+#        @widths = (10,10,10,10,10,10,10,10,10,10,10,10,10,
+#                   10,10,10,10,10,10,10,10,10,10,10,10,10)
+# Output: (3, 60)
+#
+# Line 1: abcdefghij (100 pixels)
+# Line 2: klmnopqrst (100 pixels)
+# Line 3: uvwxyz (60 pixels)
+
+# Example 2
+# Input: $str = "bbbcccdddaaa"
+#        @widths = (4,10,10,10,10,10,10,10,10,10,10,10,10,
+#                   10,10,10,10,10,10,10,10,10,10,10,10,10)
+# Output: (2, 4)
+#
+# Line 1: bbbcccdddaa (98 pixels)
+# Line 2: a (4 pixels)
+
+defmodule PWC do
+  @alphabet String.split("abcdefghijklmnopqrstuvwxyz", "", trim: true)
+
+  defp updateExplain(vars) do
+    # because this is being called with an older version of vars
+    # (before lines is incremented), we need to add one to the value
+    # in this function
+    vars[:explain] <> "\nLine " <> to_string(vars[:lines] + 1) <>
+    ": #{vars[:last_line]} (#{to_string(vars[:line_width])} pixels)"
+  end
+
+  # if the character list is empty
+  defp charCount([], _widthMap, vars) do
+    vars = %{vars |
+      explain: updateExplain(vars),
+      lines: vars[:lines] + 1
+    }
+    vars
+  end
+
+  # split the character list into the first character
+  # and all the remaining characters in the list
+  defp charCount([c | remaining], widthMap, vars) do
+    char_width = widthMap[c]
+    vars = if vars[:line_width] + char_width > 100 do
+      vars = %{vars |
+        explain: updateExplain(vars),
+        lines: vars[:lines] + 1,
+        line_width: char_width,
+        last_line: c
+      }
+      vars
+    else
+      vars = %{vars |
+        line_width: vars[:line_width] + char_width,
+        last_line: vars[:last_line] <> c
+      }
+      vars
+    end
+    charCount(remaining, widthMap, vars)
+  end
+
+  def lineCounts(str, widths) do
+    widthMap = Enum.zip(@alphabet, widths)
+             |> Map.new()
+    vars = %{
+      lines: 0,
+      line_width: 0,
+      last_line: "",
+      explain: ""
+    }
+    charCount(String.split(str, "", trim: true), widthMap, vars)
+  end
+
+  def solution(str, widths) do
+    IO.puts("Input: $str = '#{str}'")
+    IO.puts("       @widths = (#{Enum.join(widths, ", ")})")
+    vars = PWC.lineCounts(str, widths)
+    IO.puts("Output: (#{to_string(vars[:lines])}, " <>
+            "#{to_string(vars[:line_width])})#{vars[:explain]}")
+  end
+end
+
+IO.puts("Example 1:")
+PWC.solution(
+  "abcdefghijklmnopqrstuvwxyz",
+  [10,10,10,10,10,10,10,10,10,10,10,10,10,
+   10,10,10,10,10,10,10,10,10,10,10,10,10]
+)
+
+IO.puts("\nExample 2:")
+PWC.solution(
+  "bbbcccdddaaa",
+  [ 4,10,10,10,10,10,10,10,10,10,10,10,10,
+   10,10,10,10,10,10,10,10,10,10,10,10,10]
+)
+
+IO.puts("\nExample 3:")
+PWC.solution(
+  "thequickbrownfoxjumpedoverthelazydog",
+  [7,8,7,8,7,5,8,8,4,4,8,4,12,
+   8,8,8,8,5,6,4,8,8,12,8,8,7]
+)