day8 c

1 files changed, 155 insertions, 0 deletions

diff --git a/2022/day8/day8.c b/2022/day8/day8.c
new file mode 100644
index 0000000..f59322e
--- /dev/null
+++ b/2022/day8/day8.c
@@ -0,0 +1,155 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include "../util.h"
+
+s32 reduce(s32 (*f)(s32 x, s32 y), s32 arr[], s32 len)
+{
+	s32 ret = arr[0];
+
+	for (s32 i = 1; i < len; ++i) {
+		ret = f(ret, arr[i]);
+	}
+
+	return ret;
+}
+
+s32 mul(s32 x, s32 y)
+{
+	return x * y;
+}
+
+s32 max(s32 x, s32 y)
+{
+	return x > y ? x : y;
+}
+
+s32 count_char_in_string(char c, char *s)
+{
+	s32 count = 0;
+	do
+		if (c == *s)
+			count++;
+	while (*s++);
+	return count;
+}
+
+char *goto_char_in_string(char c, char *s)
+{
+	do
+		if (c == *s)
+			return s;
+	while (*s++);
+	return NULL;
+}
+
+#define PP(arr, y,x) *(*(arr+y)+x)
+
+// char filename[] = "ref.txt";
+char filename[] = "pzl.txt";
+
+#define BUF_LEN 10000
+char file_buf[BUF_LEN];
+
+int main()
+{
+	int fd = open(filename, O_RDONLY);
+	s32 data_len = read(fd, file_buf, LEN(file_buf));
+
+	if (data_len == -1) {
+		printf("error opening file\n");
+		exit(1);
+	} else if (data_len == LEN(file_buf)) {
+		printf("buffer probably not big enough\n");
+		exit(1);
+	}
+	file_buf[data_len] = '\0';
+
+	s32 y_len = count_char_in_string('\n', file_buf);
+	s32 x_len;
+	// printf("y_len: %d\n", y_len);
+
+	s32 **arr = malloc(y_len * sizeof(s32*));
+	s32 **flag = malloc(y_len * sizeof(s32*));
+	char *start  = file_buf;
+	for (s32 i = 0; i < y_len; ++i) {
+		char *end = goto_char_in_string('\n', start);
+		x_len = end - start;
+		// printf("x_len: %d\n", x_len);
+
+		*(arr+i) = malloc(x_len * sizeof(s32*));
+		*(flag+i) = malloc(x_len * sizeof(s32*));
+
+		for (s32 j = 0; j < x_len; ++j) {
+			*(*(arr+i) + j) = *(start + j) - '0';
+			*(*(flag+i) + j) = 0;
+		}
+		start = end+1;
+	}
+
+
+	s32 res1 = 0;
+	s32 maxval;
+
+#define RES1_CHECK() \
+			if (PP(arr, y, x) > maxval) {       \
+				maxval = PP(arr, y, x);     \
+				if (PP(flag, y, x) == 0) {  \
+					PP(flag, y, x) = 1; \
+					res1 += 1;          \
+				}                           \
+			}
+
+	for (s32 y = 0; y < y_len; ++y) {
+		maxval = -1;
+		for (s32 x = 0; x < x_len; ++x)
+			RES1_CHECK();
+		maxval = -1;
+		for (s32 x = x_len-1; x >= 0 ; --x)
+			RES1_CHECK();
+	}
+	for (s32 x = 0; x < x_len; ++x) {
+		maxval = -1;
+		for (s32 y = 0; y < y_len; ++y)
+			RES1_CHECK();
+		maxval = -1;
+		for (s32 y = y_len-1; y >= 0 ; --y)
+			RES1_CHECK();
+	}
+
+
+	s32 res2 = 0;
+	for (s32 y = 0; y < y_len; ++y) {
+		for (s32 x = 0; x < x_len; ++x) {
+
+			s32 rldu[4] = {0};
+			for (s32 r = x+1; r < x_len; ++r)
+				if ((PP(arr,y,r) >= PP(arr,y,x)) || (r==(x_len-1))) {
+					rldu[0] += r-x;
+					break;
+				}
+			for (s32 l = x-1; l >= 0; --l)
+				if ((PP(arr,y,l) >= PP(arr,y,x)) || (l==0)) {
+					rldu[1] += x-l;
+					break;
+				}
+			for (s32 d = y+1; d < y_len; ++d)
+				if ((PP(arr,d,x) >= PP(arr,y,x)) || (d==(y_len-1))) {
+					rldu[2] += d-y;
+					break;
+				}
+			for (s32 u = y-1; u >= 0; --u)
+				if ((PP(arr,u,x) >= PP(arr,y,x)) || (u==0)) {
+					rldu[3] += y-u;
+					break;
+				}
+			res2 = max(res2, reduce(mul, rldu, LEN(rldu)));
+		}
+	}
+
+	printf("res1: %d\n", res1);
+	printf("res2: %d\n", res2);
+	// asm("int3");
+}
+