Initial commit. Day 1 solved

.gitignore

@@ -0,0 +1,2 @@
+build/
+.cache/

Makefile

@@ -0,0 +1,22 @@
+# Advent of Code C Makefile
+
+CC = gcc
+CFLAGS = -Wall -Wextra -std=c99 -g
+
+SRCS = $(wildcard src/day*.c)
+TARGETS = $(SRCS:src/%.c=build/%)
+
+.PHONY: all
+all: $(TARGETS)
+	@echo "Compilation complete. Executables: $(TARGETS)"
+
+build/%: src/%.c
+	$(CC) $(CFLAGS) $< -o $@
+
+
+.PHONY: clean
+clean:
+	rm -f $(TARGETS)
+	@echo "Cleaned up all Advent of Code executables."
+
+.PHONY: all clean

flake.lock

@@ -0,0 +1,25 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1763948260,
+        "narHash": "sha256-dY9qLD0H0zOUgU3vWacPY6Qc421BeQAfm8kBuBtPVE0=",
+        "rev": "1c8ba8d3f7634acac4a2094eef7c32ad9106532c",
+        "revCount": 813095,
+        "type": "tarball",
+        "url": "https://api.flakehub.com/f/pinned/NixOS/nixpkgs/0.2505.813095%2Brev-1c8ba8d3f7634acac4a2094eef7c32ad9106532c/019ab6d8-0005-7317-844d-5d868444249f/source.tar.gz"
+      },
+      "original": {
+        "type": "tarball",
+        "url": "https://flakehub.com/f/NixOS/nixpkgs/0"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,26 @@
+{
+  description = "A Nix-flake-based C/C++ development environment";
+
+  inputs.nixpkgs.url =
+    "https://flakehub.com/f/NixOS/nixpkgs/0"; # stable Nixpkgs
+
+  outputs = { self, ... }@inputs:
+
+    let
+      supportedSystems =
+        [ "x86_64-linux" "aarch64-linux" "x86_64-darwin" "aarch64-darwin" ];
+      forEachSupportedSystem = f:
+        inputs.nixpkgs.lib.genAttrs supportedSystems
+        (system: f { pkgs = import inputs.nixpkgs { inherit system; }; });
+    in {
+      devShells = forEachSupportedSystem ({ pkgs }: {
+        default = pkgs.mkShell.override {
+          # stdenv = pkgs.clangStdenv;
+        } {
+          packages = with pkgs;
+            [ clang-tools clang cmake ]
+            ++ (if system == "aarch64-darwin" then [ ] else [ gdb ]);
+        };
+      });
+    };
+}

src/day1.c

@@ -0,0 +1,62 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define MAX_LINE 64
+char line[MAX_LINE + 1];
+int part1();
+int part2();
+
+int main() {
+  // printf("Result: %d", part1());
+  printf("Result: %d", part2());
+  return 0;
+}
+
+int part2() {
+  int position = 50;
+  int count = 0;
+  while (fgets(line, MAX_LINE, stdin) != NULL) {
+    position = position % 100;
+
+    line[strlen(line) - 1] = '\0';
+
+    int direction = 0;
+    if (line[0] == 'L') {
+      direction = -1;
+    } else {
+      direction = 1;
+    }
+
+    int offset = direction * atoi(&line[1]);
+
+    int full_rot = offset / 100;
+    int part_rot = offset - (100 * full_rot);
+    count += abs(full_rot) + ((part_rot < 0 && abs(part_rot) > position) ||
+                              (part_rot > 0 && (100 - position) <= part_rot));
+    position += offset;
+  }
+  return count;
+}
+
+int part1() {
+  int position = 50;
+  int count = 0;
+  while (fgets(line, MAX_LINE, stdin) != NULL) {
+    line[strlen(line) - 1] = '\0';
+
+    int direction = 0;
+    if (line[0] == 'L') {
+      direction = -1;
+    } else {
+      direction = 1;
+    }
+
+    int offset = direction * atoi(&line[1]);
+
+    position += offset;
+    count += (position % 100 == 0);
+  }
+  printf("part1 count: %d\n", count);
+  return count;
+}