Began 19

1 files changed, 77 insertions, 0 deletions

diff --git a/2020/19/solve.c b/2020/19/solve.c
new file mode 100644
index 0000000..e2868de
--- /dev/null
+++ b/2020/19/solve.c
@@ -0,0 +1,77 @@
+#include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+static char rules[256][64] = { 0 };
+
+int check_rule(char *inp, char *rule, int index)
+{
+	char ch;
+	int num1, num2, num3, num4;
+	if (sscanf(rule, "%d %d | %d %d", &num1, &num2, &num3, &num4) == 4) {
+		return (check_rule(inp, rules[num1], index) &&
+			check_rule(inp, rules[num2], index + 1)) ||
+		       (check_rule(inp, rules[num3], index) &&
+			check_rule(inp, rules[num4], index + 1));
+	} else if (sscanf(rule, "%d %d", &num1, &num2) == 2) {
+		return check_rule(inp, rules[num1], index) &&
+		       check_rule(inp, rules[num2], index + 1);
+	} else if (sscanf(rule, "\"%c\"", &ch) == 1) {
+		return ch == inp[index];
+	}
+
+	return 0;
+}
+
+long part_one(FILE *fp)
+{
+	long res = 0;
+
+	int paragraph = 0;
+	char *line = NULL;
+	size_t len;
+	while (getline(&line, &len, fp) != -1) {
+		if (line[0] == '\n') {
+			paragraph++;
+			continue;
+		}
+
+		if (paragraph == 0) {
+			char rule[64] = { 0 };
+			int ind = 0;
+			sscanf(line, "%d: %64[0-9a-z \"|]", &ind, rule);
+			strcpy(rules[ind], rule);
+		} else if (paragraph == 1) {
+			if (check_rule(line, rules[0], 0))
+				res++;
+		}
+	}
+
+	return res;
+}
+
+long part_two(FILE *fp)
+{
+	long res = 0;
+
+	return res;
+}
+
+int main(int argc, char *argv[])
+{
+	FILE *fp = fopen("input", "r");
+	if (!fp)
+		exit(EXIT_FAILURE);
+
+	clock_t tic = clock();
+	printf("%lu\n", part_one(fp));
+	rewind(fp);
+	printf("%lu\n", part_two(fp));
+	clock_t toc = clock();
+	printf("TIME: %f seconds\n", (double)(toc - tic) / CLOCKS_PER_SEC);
+
+	fclose(fp);
+	return 0;
+}