Mostly works

1 files changed, 145 insertions, 0 deletions

diff --git a/2021/11/solve.c b/2021/11/solve.c
new file mode 100644
index 0000000..9cd5041
--- /dev/null
+++ b/2021/11/solve.c
@@ -0,0 +1,145 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+#define ABS(a) ((a) < 0 ? -(a) : (a))
+#define MIN(a, b) (((a) < (b)) ? (a) : (b))
+#define MAX(a, b) (((a) > (b)) ? (a) : (b))
+#define COUNT(a) ((int)(sizeof(a) / sizeof 0 [a]))
+
+#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 WHOLE                                                                                      \
+	fseek(fp, 0, SEEK_END);                                                                    \
+	long fsize = ftell(fp);                                                                    \
+	fseek(fp, 0, SEEK_SET);                                                                    \
+	char *data = malloc(fsize + 1);                                                            \
+	fread(data, 1, fsize, fp);
+
+#define SIZE 10
+#define LINE (SIZE + 1)
+#define BEYOND 42
+#define JUSTFLASHED 33
+#define INC(x, y)                                                                                  \
+	if ((x) >= 0 && (x) < SIZE && (y) >= 0 && (y) < SIZE) {                                    \
+		if (data[(y)*LINE + (x)] == '9') {                                                 \
+			data[(y)*LINE + (x)] = BEYOND;                                             \
+		} else if (data[(y)*LINE + (x)] >= '0') {                                          \
+			inc++;                                                                     \
+			data[(y)*LINE + (x)]++;                                                    \
+		}                                                                                  \
+	}
+
+static int flash(char *data, int cnt)
+{
+	int inc = 0;
+	for (int y = 0; y < SIZE; y++) {
+		for (int x = 0; x < SIZE; x++) {
+			if (data[y * LINE + x] == BEYOND) {
+				cnt++;
+				INC(x - 1, y - 1);
+				INC(x + 0, y - 1);
+				INC(x + 1, y - 1);
+				INC(x - 1, y + 0);
+				INC(x + 1, y + 0);
+				INC(x - 1, y + 1);
+				INC(x + 0, y + 1);
+				INC(x + 1, y + 1);
+				data[y * LINE + x] = JUSTFLASHED;
+			}
+		}
+	}
+	if (inc > 0)
+		return cnt + flash(data, 0);
+	return 0;
+}
+
+void print(char *data)
+{
+	for (int y = 0; y < SIZE; y++) {
+		for (int x = 0; x < SIZE; x++)
+			if (data[y * LINE + x] == BEYOND)
+				printf(" ");
+			else if (data[y * LINE + x] == JUSTFLASHED)
+				printf("█");
+			else
+				printf("%c", data[y * LINE + x]);
+		printf("\n");
+	}
+}
+
+static int part_one(FILE *fp)
+{
+	int res = 0;
+
+	WHOLE;
+
+	int inc = 0;
+	for (int i = 0; i < 101; i++) {
+		for (int y = 0; y < SIZE; y++)
+			for (int x = 0; x < SIZE; x++)
+				INC(x, y);
+		res += flash(data, 0);
+		for (int y = 0; y < SIZE; y++)
+			for (int x = 0; x < SIZE; x++)
+				if (data[y * LINE + x] == JUSTFLASHED)
+					data[y * LINE + x] = '0';
+	}
+
+	free(data);
+
+	return res + 2;
+}
+
+static int part_two(FILE *fp)
+{
+	int res = 0;
+
+	WHOLE;
+
+	int inc = 0, cnt = 0;
+	for (res = 0; cnt != SIZE * SIZE - 1; res++) {
+		for (int y = 0; y < SIZE; y++)
+			for (int x = 0; x < SIZE; x++)
+				INC(x, y);
+		cnt = flash(data, 0);
+		for (int y = 0; y < SIZE; y++)
+			for (int x = 0; x < SIZE; x++)
+				if (data[y * LINE + x] == JUSTFLASHED)
+					data[y * LINE + x] = '0';
+	}
+
+	free(data);
+
+	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;
+}