summary refs log tree commit diff homepage
path: root/2021/day13.c
blob: 3e60177c6c2e703a0706d58dff47d3814c56f5e7 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
#include <stdio.h>
#include <stdlib.h>
static int h, w;
static int paper[2048][2048];
static void foldY(int fold) {
	for (int y = 0; y < fold; ++y)
	for (int x = 0; x < w; ++x) {
		paper[y][x] |= paper[h-1-y][x];
	}
	h = fold;
}
static void foldX(int fold) {
	for (int x = 0; x < fold; ++x)
	for (int y = 0; y < h; ++y) {
		paper[y][x] |= paper[y][w-1-x];
	}
	w = fold;
}
static int sum(void) {
	int sum = 0;
	for (int y = 0; y < h; ++y)
	for (int x = 0; x < w; ++x) {
		sum += paper[y][x];
	}
	return sum;
}
int main(void) {
	int x, y;
	while (2 == scanf("%d,%d\n", &x, &y)) {
		paper[y][x] = 1;
		if (y >= h) h = y+1;
		if (x >= w) w = x+1;
	}
	char axis;
	int fold;
	int first = 1;
	while (EOF != scanf(" fold along %c=%d\n", &axis, &fold)) {
		if (axis == 'y') {
			foldY(fold);
		} else if (axis == 'x') {
			foldX(fold);
		} else {
			printf("??? %c\n", axis);
		}
		if (first) {
			printf("%d\n", sum());
			first = 0;
		}
	}
	for (int y = 0; y < h; ++y) {
		for (int x = 0; x < w; ++x) {
			printf("%c", (paper[y][x] ? '#' : '.'));
		}
		printf("\n");
	}
}