From 3aa641542918765f6ceb039cfa64ff6f58597eb2 Mon Sep 17 00:00:00 2001
From: Marvin Borner
Date: Tue, 30 Nov 2021 21:53:46 +0100
Subject: Hype for tomorrow

---
 2015/03/solve.c | 97 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 97 insertions(+)
 create mode 100644 2015/03/solve.c

(limited to '2015/03/solve.c')

diff --git a/2015/03/solve.c b/2015/03/solve.c
new file mode 100644
index 0000000..8f4e9ad
--- /dev/null
+++ b/2015/03/solve.c
@@ -0,0 +1,97 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+#define FORLINE                                                                                    \
+	char *line = NULL;                                                                         \
+	size_t len = 0;                                                                            \
+	while (getline(&line, &len, fp) != EOF)
+#define FREELINE                                                                                   \
+	if (line)                                                                                  \
+	free(line)
+
+#define FORCH                                                                                      \
+	char ch = 0;                                                                               \
+	while ((ch = fgetc(fp)) != EOF)
+
+#define INFINITE 1024
+static int part_one(FILE *fp)
+{
+	int res = 1;
+	char houses[INFINITE * 2][INFINITE * 2] = { 0 };
+	int x = INFINITE, y = INFINITE;
+
+	houses[x][y] = 1;
+	FORCH
+	{
+		if (ch == '>')
+			x++;
+		else if (ch == '<')
+			x--;
+		else if (ch == '^')
+			y++;
+		else if (ch == 'v')
+			y--;
+
+		if (!houses[x][y]) {
+			houses[x][y] = 1;
+			res++;
+		}
+	}
+
+	return res;
+}
+
+static int part_two(FILE *fp)
+{
+	int res = 1;
+
+	char houses[INFINITE * 2][INFINITE * 2] = { 0 };
+	int rx = INFINITE, ry = INFINITE, sx = INFINITE, sy = INFINITE;
+
+	houses[sx][sy] = 1;
+	int robo = 0;
+	FORCH
+	{
+		int *x = robo ? &rx : &sx;
+		int *y = robo ? &ry : &sy;
+
+		if (ch == '>')
+			(*x)++;
+		else if (ch == '<')
+			(*x)--;
+		else if (ch == '^')
+			(*y)++;
+		else if (ch == 'v')
+			(*y)--;
+
+		if (!houses[*x][*y]) {
+			houses[*x][*y] = 1;
+			res++;
+		}
+
+		robo = !robo;
+	}
+
+	return res;
+}
+
+int main(int argc, char *argv[])
+{
+	(void)argc;
+	(void)argv;
+
+	FILE *fp = fopen("input", "r");
+	if (!fp)
+		exit(EXIT_FAILURE);
+
+	clock_t tic = clock();
+	printf("%d\n", part_one(fp));
+	rewind(fp);
+	printf("%d\n", part_two(fp));
+	clock_t toc = clock();
+	printf("TIME: %f seconds\n", (double)(toc - tic) / CLOCKS_PER_SEC);
+
+	fclose(fp);
+	return 0;
+}
-- 
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