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use fmt;
use io;
use os;
use strconv;
use strings::{fromutf8_unsafe, split, torunes};
const adjacent_positions: [8][2]int = [
[-1, -1],
[ 0, -1],
[ 1, -1],
[-1, 0],
[ 1, 0],
[-1, 1],
[ 0, 1],
[ 1, 1]
];
fn adjacent_rolls(grid: [][]rune, x: int, y: int) u64 = {
let rolls: u64 = 0;
for (let pos .. adjacent_positions) {
let col = x: int + pos[0];
let row = y: int + pos[1];
if (col < 0 || col >= len(grid[0]): int ||
row < 0 || row >= len(grid): int)
continue;
if (grid[row][col] == '@')
rolls += 1;
};
return rolls;
};
export fn main() void = {
let handle = os::open("input.txt")!;
defer io::close(handle)!;
let buf = io::drain(handle)!;
defer free(buf);
let lines = split(fromutf8_unsafe(buf), "\n")!;
let grid: [][]rune = [];
let total_removable_rolls: u64 = 0;
let removed_rolls: u64 = 666;
for (let line .. lines) {
if (line != "")
append(grid, torunes(line)!)!;
};
for (removed_rolls > 0) {
removed_rolls = 0;
for (let x: size = 0; x < len(grid[0]); x += 1) {
for (let y: size = 0; y < len(grid); y += 1) {
if (grid[y][x] == '@' &&
adjacent_rolls(grid, x: int, y: int) < 4) {
grid[y][x] = '.';
total_removable_rolls += 1;
removed_rolls += 1;
};
};
};
};
fmt::printfln("Answer: {}", total_removable_rolls)!;
};
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