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const std = @import("std");
const aoc = @import("aoc");
fn PosVec(comptime N: u32) type {
return struct { data: [N]i64 };
}
const Active = bool;
fn forNeighbors(comptime dims: u32, map: *std.AutoHashMap(PosVec(dims), Active), p: PosVec(dims), data: anytype, func: fn (map: *std.AutoHashMap(PosVec(dims), Active), p: PosVec(dims), d: @TypeOf(data)) anyerror!void) !void {
var i: u32 = 0;
while (i < comptime std.math.pow(u32, 3, dims)) : (i += 1) {
var np: PosVec(dims) = undefined;
var d: u32 = 0;
var skip = true;
while (d < dims) : (d += 1) {
const offset = (i / std.math.pow(u32, 3, d)) % 3;
np.data[d] = p.data[d] + @intCast(i64, offset) - 1;
if (skip and offset != 1) skip = false;
}
if (skip) continue;
try func(map, np, data);
}
}
fn posStr(comptime dims: u32, p: PosVec(dims)) void {
var d: u32 = 0;
while (d < dims) : (d += 1) {
aoc.debugfmt("{} ", .{p.data[d]});
}
}
fn countActive(comptime dims: u32) fn (map: *std.AutoHashMap(PosVec(dims), Active), p: PosVec(dims), d: *u32) anyerror!void {
const impl = struct {
fn func(map: *std.AutoHashMap(PosVec(dims), Active), p: PosVec(dims), d: *u32) anyerror!void {
d.* += @boolToInt(map.get(p) != null);
}
};
return impl.func;
}
fn addNew(comptime dims: u32) fn (oldmap: *std.AutoHashMap(PosVec(dims), Active), p: PosVec(dims), newmap: *std.AutoHashMap(PosVec(dims), Active)) anyerror!void {
const impl = struct {
fn func(oldmap: *std.AutoHashMap(PosVec(dims), Active), p: PosVec(dims), newmap: *std.AutoHashMap(PosVec(dims), Active)) anyerror!void {
if (newmap.get(p) != null) return;
var v = oldmap.get(p);
var state = (v != null);
var count: u32 = 0;
try forNeighbors(dims, oldmap, p, &count, countActive(dims));
if (state and count >= 2 and count <= 3 or !state and count == 3) {
try newmap.put(p, true);
}
}
};
return impl.func;
}
fn simulateRound(comptime dims: u32, map: *std.AutoHashMap(PosVec(dims), Active), allocator: std.mem.Allocator) !void {
var newmap = std.AutoHashMap(PosVec(dims), Active).init(allocator);
errdefer newmap.deinit();
var mapit = map.iterator();
while (mapit.next()) |kv| {
try forNeighbors(dims, map, kv.key_ptr.*, &newmap, addNew(dims));
try addNew(dims)(map, kv.key_ptr.*, &newmap);
}
std.mem.swap(std.AutoHashMap(PosVec(dims), Active), map, &newmap);
newmap.deinit();
}
fn sliceProduct(data: []i64) i64 {
var product: i64 = 1;
for (data) |v| {
product *= v;
}
return product;
}
fn printMap(comptime dims: u32, map: *std.AutoHashMap(PosVec(dims), Active)) void {
var min: ?PosVec(dims) = null;
var max: ?PosVec(dims) = null;
var mapit = map.iterator();
while (mapit.next()) |kv| {
if (min == null) min = kv.key_ptr.*;
if (max == null) max = kv.key_ptr.*;
var d: u32 = 0;
while (d < dims) : (d += 1) {
if (min.?.data[d] > kv.key_ptr.data[d]) min.?.data[d] = kv.key_ptr.data[d];
if (max.?.data[d] < kv.key_ptr.data[d]) max.?.data[d] = kv.key_ptr.data[d];
}
}
if (min == null or max == null) return;
var space: PosVec(dims) = undefined;
{
var d: u32 = 0;
while (d < dims) : (d += 1) {
space.data[d] = max.?.data[d] - min.?.data[d];
}
}
var i: usize = 0;
while (i < sliceProduct(space.data[0..])) : (i += @intCast(usize, space.data[0] * space.data[1])) {
var np: PosVec(dims) = undefined;
var d: u32 = 0;
while (d < dims) : (d += 1) {
np.data[d] = min.?.data[d] + @mod(@divFloor(@intCast(i64, i), sliceProduct(space.data[0..d])), space.data[d]);
}
d = 2;
aoc.debugfmt("Slice at: ", .{});
while (d < dims) : (d += 1) {
if (d > 2) aoc.debugfmt(",", .{});
aoc.debugfmt("{}.Dim = {} ", .{ d + 1, np.data[d] });
}
aoc.debugfmt("\n", .{});
var y = min.?.data[1];
while (y <= max.?.data[1]) : (y += 1) {
var x = min.?.data[0];
while (x <= max.?.data[0]) : (x += 1) {
var v = np;
v.data[0] = x;
v.data[1] = y;
var c: u8 = '.';
if (map.get(v) != null) c = '#';
aoc.debugfmt("{c}", .{c});
}
aoc.debugfmt("\n", .{});
}
aoc.debugfmt("\n", .{});
}
}
fn part1(allocator: std.mem.Allocator, input: []u8, args: [][]u8) !?[]u8 {
_ = args;
var map = std.AutoHashMap(PosVec(3), Active).init(allocator);
defer map.deinit();
var lineit = std.mem.tokenize(u8, input, "\n");
var y: i64 = 0;
while (lineit.next()) |line| : (y += 1) {
for (line) |c, x| {
if (c != '#') continue;
try map.put(PosVec(3){ .data = [_]i64{ @intCast(i64, x), y, 0 } }, true);
}
}
var i: usize = 0;
while (i < 6) : (i += 1) {
try simulateRound(3, &map, allocator);
if (aoc.debug) {
aoc.debugfmt("AFTER ROUND {}:\n", .{i + 1});
printMap(3, &map);
}
}
return try std.fmt.allocPrint(allocator, "{}", .{map.count()});
}
fn part2(allocator: std.mem.Allocator, input: []u8, args: [][]u8) !?[]u8 {
_ = args;
var map = std.AutoHashMap(PosVec(4), Active).init(allocator);
defer map.deinit();
var lineit = std.mem.tokenize(u8, input, "\n");
var y: i64 = 0;
while (lineit.next()) |line| : (y += 1) {
for (line) |c, x| {
if (c != '#') continue;
try map.put(PosVec(4){ .data = [_]i64{ @intCast(i64, x), y, 0, 0 } }, true);
}
}
var i: usize = 0;
while (i < 6) : (i += 1) {
try simulateRound(4, &map, allocator);
if (aoc.debug) {
aoc.debugfmt("AFTER ROUND {}:\n", .{i + 1});
printMap(4, &map);
}
}
return try std.fmt.allocPrint(allocator, "{}", .{map.count()});
}
pub const main = aoc.main(part1, part2, .{ "304", "1868" });
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