Merge pull request #3 from MaximumGeeker/master

[langlearn/.git] / towers_of_hanoi / lua / MaximumGeeker / hanoi.lua

diff --git a/towers_of_hanoi/lua/MaximumGeeker/hanoi.lua b/towers_of_hanoi/lua/MaximumGeeker/hanoi.lua
new file mode 100644 (file)
index 0000000..95771f1
--- /dev/null
+++ b/towers_of_hanoi/lua/MaximumGeeker/hanoi.lua
@@ -0,0 +1,42 @@
+--[[ Towers of hanoi - Lua 5.1 ]]--
+
+local move = function(a, b)
+  print( a, '->', b )
+end
+
+local hanoi
+hanoi = function(n, orig, pivot, dest)
+  if n < 1 then
+    return
+  end
+
+  if n == 1 then
+    move( orig, dest )
+    return
+  end
+
+  if n == 2 then
+    move( orig, pivot )
+    move( orig, dest )
+    move( pivot, dest )
+    return
+  end
+
+  hanoi(n-2, orig, pivot, dest)
+  move( orig, pivot )
+  hanoi(n-2, dest, orig, pivot)
+  move( orig, dest )
+  hanoi(n-1, pivot, orig, dest)
+end
+
+io.write "Value of N: "
+local n = io.read "*n"
+
+if type(n) == 'number' then
+  n = math.floor(n)
+else
+  io.stderr "Value given is not a number.\n"
+  os.exit(1)
+end
+
+hanoi(n, 'Left', 'Center', 'Right')