Data update

Task/Pascal-matrix-generation/Elixir/pascal-matrix-generation.ex

@@ -0,0 +1,46 @@
+defmodule Pascal do
+  defp ij(n), do: for i <- 1..n, j <- 1..n, do: {i,j}
+
+  def upper_triangle(n) do
+    Enum.reduce(ij(n), Map.new, fn {i,j},acc ->
+      val = cond do
+              i==1 -> 1
+              j<i  -> 0
+              true -> Map.get(acc, {i-1, j-1}) + Map.get(acc, {i, j-1})
+            end
+      Map.put(acc, {i,j}, val)
+    end) |> print(1..n)
+  end
+
+  def lower_triangle(n) do
+    Enum.reduce(ij(n), Map.new, fn {i,j},acc ->
+      val = cond do
+              j==1 -> 1
+              i<j  -> 0
+              true -> Map.get(acc, {i-1, j-1}) + Map.get(acc, {i-1, j})
+            end
+      Map.put(acc, {i,j}, val)
+    end) |> print(1..n)
+  end
+
+  def symmetic_triangle(n) do
+    Enum.reduce(ij(n), Map.new, fn {i,j},acc ->
+      val = if i==1 or j==1, do: 1,
+                           else: Map.get(acc, {i-1, j}) + Map.get(acc, {i, j-1})
+      Map.put(acc, {i,j}, val)
+    end) |> print(1..n)
+  end
+
+  def print(matrix, range) do
+    Enum.each(range, fn i ->
+      Enum.map(range, fn j -> Map.get(matrix, {i,j}) end) |> IO.inspect
+    end)
+  end
+end
+
+IO.puts "Pascal upper-triangular matrix:"
+Pascal.upper_triangle(5)
+IO.puts "Pascal lower-triangular matrix:"
+Pascal.lower_triangle(5)
+IO.puts "Pascal symmetric matrix:"
+Pascal.symmetic_triangle(5)