blob: a6793d7ce264dd36ddfcfcfb5a444f51d7fbd03a (
plain)
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
57
58
59
|
const std = @import("std");
pub fn adj(list: std.ArrayList([]u8), x: usize, y: usize) u8 {
var count: u8 = 0;
if(y > 0 and list.items[y - 1][x] == '@') count += 1;
if(y < list.items.len - 1 and list.items[y + 1][x] == '@') count += 1;
if(x > 0 and list.items[y][x - 1] == '@') count += 1;
if(x < list.items[0].len - 1 and list.items[y][x + 1] == '@') count += 1;
if(y > 0 and x > 0 and list.items[y - 1][x - 1] == '@') count += 1;
if(y < list.items.len - 1 and x > 0 and list.items[y + 1][x - 1] == '@') count += 1;
if(y > 0 and x < list.items[0].len - 1 and list.items[y - 1][x + 1] == '@') count += 1;
if(y < list.items.len - 1 and x < list.items[0].len - 1 and list.items[y + 1][x + 1] == '@') count += 1;
return count;
}
pub fn main() !void {
var gpa = std.heap.GeneralPurposeAllocator(.{}){};
defer _ = gpa.deinit();
const alloc = gpa.allocator();
const path = "input.txt";
const fp = try std.fs.cwd().openFile(path, .{.mode = std.fs.File.OpenMode.read_only});
defer fp.close();
var reader = fp.reader();
var buffer: [256]u8 = undefined;
var list = std.ArrayList([]u8).init(alloc);
defer list.deinit();
defer for(list.items) |i| alloc.free(i);
while(try reader.readUntilDelimiterOrEof(&buffer, '\n')) |line| {
var linec = try alloc.alloc(u8, 256);
@memset(linec, 0);
@memcpy(linec[0..line.len], line);
try list.append(linec);
}
var count: u64 = 0;
var y: isize = 0;
while(y < list.items.len) : (y += 1) {
var x: usize = 0;
while(x < list.items[0].len) : (x += 1){
if(list.items[@intCast(y)][x] == '@' and adj(list, x, @intCast(y)) < 4) {
list.items[@intCast(y)][x] = '.';
if(y != 0) y -= 1;
y -= 1;
count += 1;
break;
}
}
}
std.debug.print("{d}\n", .{count});
}
|
