adventofcode2021/day02/part1.nim

51 lines
1.3 KiB
Nim

# 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())