add day2 solution

day02/part1.nim

@@ -0,0 +1,50 @@
+# Copyright 2021 Christian Ulrich
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# usage: ./part1 < input
+
+import strutils
+
+proc position(): int =
+  var
+    line = ""
+    hpos = 0
+    vpos = 0
+  while readLine(stdin, line):
+    if line.len() > 0:
+      let command = line.split(' ', 1)
+      if command.len() != 2:
+        raise newException(ValueError, "invalid command")
+      let arg = parseInt(command[1])
+      case command[0]
+      of "forward":
+        hpos.inc(arg)
+      of "up":
+        vpos.dec(arg)
+      of "down":
+        vpos.inc(arg)
+      else:
+        raise newException(ValueError, "invalid command")
+  result = hpos * vpos
+
+proc main(): int =
+  try:
+    echo position()
+  except Exception as error:
+    echo error.msg
+    result = -1
+
+when isMainModule:
+  quit(main())

day02/part2.nim

@@ -0,0 +1,52 @@
+# Copyright 2021 Christian Ulrich
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# usage: ./part2 < input
+
+import strutils
+
+proc position(): int =
+  var
+    line = ""
+    aim = 0
+    hpos = 0
+    vpos = 0
+  while readLine(stdin, line):
+    if line.len() > 0:
+      let command = line.split(' ', 1)
+      if command.len() != 2:
+        raise newException(ValueError, "invalid command")
+      let arg = parseInt(command[1])
+      case command[0]
+      of "forward":
+        hpos.inc(arg)
+        vpos.inc(aim * arg)
+      of "up":
+        aim.dec(arg)
+      of "down":
+        aim.inc(arg)
+      else:
+        raise newException(ValueError, "invalid command")
+  result = hpos * vpos
+
+proc main(): int =
+  try:
+    echo position()
+  except Exception as error:
+    echo error.msg
+    result = -1
+
+when isMainModule:
+  quit(main())

day02/testinput

@@ -0,0 +1,6 @@
+forward 5
+down 5
+forward 8
+up 3
+down 8
+forward 2