day 2 init

2021/day02/EXAMPLE.txt

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+forward 5
+down 5
+forward 8
+up 3
+down 8
+forward 2

2021/day02/Makefile

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+# AOC daily Makefile - GNU make only.
+#
+# Copyright (C) 2021 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.htmlL>.
+#
+# SPDX-License-Identifier: GPL-3.0-or-later <https://spdx.org/licenses/GPL-3.0-or-later.html>
+#
+
+INPUT   := INPUT.txt
+SHELL   := /bin/bash
+
+CC      := gcc
+
+LIB     := aoc_$(shell uname -m)
+INCDIR  := ../include
+LIBDIR  := ../lib
+LDFLAGS := -L$(LIBDIR)
+LDLIB   := -l$(LIB)
+
+export LD_LIBRARY_PATH = $(LIBDIR)
+
+CFLAGS += -std=gnu99
+CFLAGS += -O2
+CFLAGS += -g
+CFLAGS += -Wall
+CFLAGS += -Wextra
+CFLAGS += -march=native
+
+CFLAGS += -DDEBUG_POOL              # memory pools management
+
+TIME   := \time -f "\ttime: %E real, %U user, %S sys\n\tcontext-switch:\t%c+%w, page-faults: %F+%R\n"
+export PATH := .:$(PATH)
+
+.PHONY: clean all compile deploy ex1 ex2
+
+all: ex1 ex2
+
+compile: aoc-c
+
+ex1: aoc-c
+	@$(TIME) aoc-c -d 5 -p 1 < $(INPUT)
+
+ex2: aoc-c
+	@$(TIME) aoc-c -d 5 -p 2 < $(INPUT)
+
+clean:
+	@rm -f aoc-c core*
+
+.c:
+	@echo compiling $<
+	@$(CC) $(CFLAGS) $(LDFLAGS) -I $(INCDIR) $< $(LDLIB) -o $@

2021/day02/README.txt

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+--- Day 2: Dive! ---
+
+Now, you need to figure out how to pilot this thing.
+
+It seems like the submarine can take a series of commands like forward 1, down 2, or up 3:
+
+    forward X increases the horizontal position by X units.
+    down X increases the depth by X units.
+    up X decreases the depth by X units.
+
+Note that since you're on a submarine, down and up affect your depth, and so they have the opposite result of what you might expect.
+
+The submarine seems to already have a planned course (your puzzle input). You should probably figure out where it's going. For example:
+
+forward 5
+down 5
+forward 8
+up 3
+down 8
+forward 2
+
+Your horizontal position and depth both start at 0. The steps above would then modify them as follows:
+
+    forward 5 adds 5 to your horizontal position, a total of 5.
+    down 5 adds 5 to your depth, resulting in a value of 5.
+    forward 8 adds 8 to your horizontal position, a total of 13.
+    up 3 decreases your depth by 3, resulting in a value of 2.
+    down 8 adds 8 to your depth, resulting in a value of 10.
+    forward 2 adds 2 to your horizontal position, a total of 15.
+
+After following these instructions, you would have a horizontal position of 15 and a depth of 10. (Multiplying these together produces 150.)
+
+Calculate the horizontal position and depth you would have after following the planned course. What do you get if you multiply your final horizontal position by your final depth?
+
+To begin, get your puzzle input.
+
+Answer:
+
+You can also [Shareon Mastodon] this puzzle.