2022 day 10: Bash parts 1 & 2

2022/day10/aoc.bash

@@ -0,0 +1,68 @@
+#!/usr/bin/env bash
+#
+# aoc.bash: Advent of Code 2022, day 10
+#
+# Copyright (C) 2022 Bruno Raoult ("br")
+# Licensed under the GNU General Public License v3.0 or later.
+# Some rights reserved. See COPYING.
+#
+# You should have received a copy of the GNU General Public License along with this
+# program. If not, see <https://www.gnu.org/licenses/gpl-3.0-standalone.html>.
+#
+# SPDX-License-Identifier: GPL-3.0-or-later <https://spdx.org/licenses/GPL-3.0-or-later.html>
+
+. common.bash
+
+declare -i cycle=0 regx=1
+
+draw() {
+    local -i pos
+
+    if (( cycle % 40 )); then
+        (( pos = cycle % 40 - regx - 1, pos = pos < 0? -pos: pos ))
+        (( pos < 2 )) && res+="#" || res+="."
+    else
+        res+=.$'\n'
+    fi
+}
+
+tick() {
+    (( cycle ++ ))
+    if (( part == 1 )); then
+        (( (cycle + 20) % 40 )) || (( res += cycle * regx ))
+    else
+        draw
+    fi
+}
+
+do_noop() {
+    tick
+}
+
+do_add() {
+    tick
+    tick
+    (( regx += $1 ))
+}
+
+parse() {
+    while read -r instr value; do
+        # not too hacky, to prepare for next puzzles ;-)
+        case "$instr" in
+            "addx")
+                do_add "$value"
+                ;;
+            "noop")
+                do_noop
+                ;;
+        esac
+    done
+}
+
+solve() {
+    # remove last '\n', add starting '\n'
+    (( part == 2 )) && res=$'\n'${res::-1}
+}
+
+main "$@"
+exit 0