Started 16th solution

1 files changed, 95 insertions, 0 deletions

diff --git a/2020/16/solve.c b/2020/16/solve.c
new file mode 100644
index 0000000..119791b
--- /dev/null
+++ b/2020/16/solve.c
@@ -0,0 +1,95 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+struct rule {
+	int low1;
+	int high1;
+	int low2;
+	int high2;
+};
+
+int solve(FILE *fp)
+{
+	// Part one
+	char *line = NULL;
+	size_t len = 0;
+	int paragraph = 0;
+	char name[64];
+	char valid[256][128];
+	int invalid[4096] = { 0 };
+	struct rule rules[64] = { 0 };
+	int rule_cnt = 0, invalid_cnt = 0, valid_cnt = 0;
+	while (getline(&line, &len, fp) != -1) {
+		if (line[0] == '\n') {
+			paragraph++;
+			continue;
+		}
+		if (paragraph == 0) {
+			int low1, high1, low2, high2;
+			sscanf(line, "%[^:]: %u-%u or %u-%u\n", name, &low1, &high1, &low2, &high2);
+			struct rule rule = {
+				.low1 = low1, .high1 = high1, .low2 = low2, .high2 = high2
+			};
+			rules[rule_cnt++] = rule;
+		} else if (paragraph == 2) {
+			if (line[0] == 'n')
+				continue;
+
+			int num;
+			int bytes_now, bytes_consumed = 0;
+
+			int invalid_ticket = 0;
+			while (sscanf(line + bytes_consumed, "%d,%n", &num, &bytes_now) > 0) {
+				int inc = 0;
+				for (int i = 0; i < rule_cnt; i++) {
+					struct rule rule = rules[i];
+					if ((num >= rule.low1 && num <= rule.high1) ||
+					    (num >= rule.low2 && num <= rule.high2)) {
+						inc = 0;
+						break;
+					} else {
+						inc = num;
+					}
+				}
+				if (inc) {
+					invalid[invalid_cnt++] = num;
+					invalid_ticket = 1;
+				}
+
+				bytes_consumed += bytes_now;
+			}
+			if (!invalid_ticket)
+				strcpy(valid[valid_cnt++], line);
+		}
+	}
+
+	int cnt = 0;
+	for (int i = 0; i < invalid_cnt; i++) {
+		cnt += invalid[i];
+	}
+	printf("%d\n", cnt);
+
+	// Part two
+	for (int i = 0; i < valid_cnt; i++) {
+		//printf("%s", valid[i]);
+	}
+
+	return 0;
+}
+
+int main(int argc, char *argv[])
+{
+	FILE *fp = fopen("input", "r");
+	if (!fp)
+		exit(EXIT_FAILURE);
+
+	clock_t tic = clock();
+	printf("%d\n", solve(fp));
+	clock_t toc = clock();
+	printf("TIME: %f seconds\n", (double)(toc - tic) / CLOCKS_PER_SEC);
+
+	fclose(fp);
+	return 0;
+}