advent-of-code

commit 7c2caea1b2df31b38e53c41606c550fffdc62774
parent c5680be46599039605d5f756896a33f7b4749a7d
Author: aabacchus <bvnfuller@gmail.com>
Date:   Thu,  2 Dec 2021 21:16:53 +0000

21.2.1 in C

this, on the other hand, took about seven minutes.

Diffstat:
A
2021/02/2.c
 | 
48
++++++++++++++++++++++++++++++++++++++++++++++++

1 file changed, 48 insertions(+), 0 deletions(-)
diff --git a/2021/02/2.c b/2021/02/2.c
@@ -0,0 +1,48 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+int
+main(int argc, char **argv) {
+	if (argc < 2) {
+		fprintf(stderr, "usage: %s datafile\n", *argv);
+		return 1;
+	}
+
+	FILE *fd = fopen(argv[1], "r");
+	if (fd == NULL) {
+		perror(argv[1]);
+		return 1;
+	}
+
+	int coords[2] = {0, 0};
+
+	char *buf = NULL;
+	size_t buflen = 0;
+	while (getline(&buf, &buflen, fd) != -1) {
+		int param = atoi(strchr(buf, ' ') + 1);
+		switch (buf[0]) {
+			case 'f': /* forward */
+				coords[0] += param;
+				break;
+			case 'u': /* up */
+				coords[1] -= param;
+				break;
+			case 'd': /* down */
+				coords[1] += param;
+				break;
+		}
+	}
+
+	free(buf);
+
+	printf("final coords: %d %d\n", coords[0], coords[1]);
+	printf("product: %d\n", coords[0] * coords[1]);
+
+	if (fclose(fd) == EOF) {
+		perror("fclose");
+		return 1;
+	}
+	
+	return 0;
+}