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const std = @import("std");
const day4 = @import("day4");
test "idx test" {
var gpa = std.heap.GeneralPurposeAllocator(.{}){};
defer _ = gpa.deinit();
const alloc = gpa.allocator();
// Read contents from file "./filename"
const cwd = std.fs.cwd();
const fileContents = try cwd.readFileAlloc(alloc, "day4_test.txt", 24000);
defer alloc.free(fileContents);
// Print file contents
// std.debug.print("{s}", .{fileContents});
var lines = std.mem.splitScalar(u8, fileContents, '\n');
const line = lines.peek() orelse unreachable;
const col_count = line.len;
var grid = std.array_list.Aligned(bool, null).empty;
defer grid.deinit(alloc);
// put in all @
var r: u64 = 0;
while (lines.next()) |row| : (r += 1) {
if (row.len == 0) {
break;
}
std.debug.print("row: {s}\n", .{row});
for (row) |v| {
if (v == '@') {
try grid.append(alloc, true);
} else {
try grid.append(alloc, false);
}
}
}
// const row_count = r / col_count;
try std.testing.expect(grid.items[idx(0, 0, col_count)] == false);
try std.testing.expect(grid.items[idx(0, 1, col_count)] == false);
try std.testing.expect(grid.items[idx(0, 2, col_count)] == true);
try std.testing.expect(grid.items[idx(0, 3, col_count)] == true);
try std.testing.expect(grid.items[idx(0, 4, col_count)] == false);
try std.testing.expect(grid.items[idx(0, 5, col_count)] == true);
try std.testing.expect(grid.items[idx(0, 6, col_count)] == true);
try std.testing.expect(grid.items[idx(0, 7, col_count)] == true);
try std.testing.expect(grid.items[idx(0, 8, col_count)] == true);
try std.testing.expect(grid.items[idx(0, 9, col_count)] == false);
try std.testing.expect(grid.items[idx(1, 0, col_count)] == true);
try std.testing.expect(grid.items[idx(1, 1, col_count)] == true);
try std.testing.expect(grid.items[idx(1, 2, col_count)] == true);
try std.testing.expect(grid.items[idx(1, 3, col_count)] == false);
try std.testing.expect(grid.items[idx(1, 4, col_count)] == true);
try std.testing.expect(grid.items[idx(1, 5, col_count)] == false);
try std.testing.expect(grid.items[idx(1, 6, col_count)] == true);
try std.testing.expect(grid.items[idx(1, 7, col_count)] == false);
try std.testing.expect(grid.items[idx(1, 8, col_count)] == true);
try std.testing.expect(grid.items[idx(1, 9, col_count)] == true);
}
const Position = struct {
row: u64,
col: u64,
};
fn idx(r: usize, c: usize, col_count: usize) usize {
return r * col_count + c;
}
const MAX_POTENTIAL_CHANGES = 8;
const AppendError = error{Full};
fn append(arr: *[MAX_POTENTIAL_CHANGES]Position, arr_len: *usize, val: Position) (AppendError!void) {
if (arr_len.* >= arr.*.len) {
return error.Full;
}
arr[arr_len.*] = val;
arr_len.* += 1;
}
pub fn main() !void {
// Initiate allocator
var gpa = std.heap.GeneralPurposeAllocator(.{}){};
defer _ = gpa.deinit();
const alloc = gpa.allocator();
// Read contents from file "./filename"
const cwd = std.fs.cwd();
const fileContents = try cwd.readFileAlloc(alloc, "day4.txt", 24000);
defer alloc.free(fileContents);
// Print file contents
// std.debug.print("{s}", .{fileContents});
var lines = std.mem.splitScalar(u8, fileContents, '\n');
const line = lines.peek() orelse unreachable;
const col_count = line.len;
var accessible_rolls: u64 = 0;
var changes = std.array_list.Aligned(Position, null).empty;
defer changes.deinit(alloc);
var grid = std.array_list.Aligned(bool, null).empty;
defer grid.deinit(alloc);
var next_grid = std.array_list.Aligned(bool, null).empty;
defer next_grid.deinit(alloc);
// put in all @
var r: u64 = 0;
while (lines.next()) |row| : (r += 1) {
if (row.len == 0) {
break;
}
std.debug.print("row: {s}\n", .{row});
for (row, 0..) |v, c| {
if (v == '@') {
try changes.append(alloc, Position{ .row = r, .col = c });
try grid.append(alloc, true);
} else {
try grid.append(alloc, false);
}
}
}
const row_count = r;
try next_grid.resize(alloc, grid.items.len);
@memcpy(next_grid.items, grid.items);
var current_head: usize = 0;
var changes_made = true;
std.debug.print("COL_COUNT:{}, ROW_COUNT:{}\n\n\n", .{ col_count, row_count });
var seen = std.hash_map.AutoHashMap(Position, bool).init(alloc);
defer seen.deinit();
while (changes_made) {
for (grid.items, 0..) |value, j| {
if (j % col_count == 0 and j != 0) {
std.debug.print("\n", .{});
}
if (value) {
std.debug.print("@", .{});
} else {
std.debug.print(".", .{});
}
}
std.debug.print("\n", .{});
const current_changes_len = changes.items.len;
for (current_head..current_changes_len) |i| {
const pos = changes.items[i];
if (seen.get(pos) orelse false) {
continue;
}
var potential_changes: [MAX_POTENTIAL_CHANGES]Position = undefined;
var potential_changes_len: usize = 0;
std.debug.print("index: i{}, current head{} current_changes_len{} | ", .{ i, current_head, current_changes_len });
std.debug.print("Position: [{}, {}] idx{} | ", .{ pos.row, pos.col, idx(pos.row, pos.col, col_count) });
// if (!grid.items[idx(pos.row, pos.col, col_count)]) {
// continue;
// }
var surrounding: u64 = 0;
if (pos.row > 0) {
if (pos.col > 0) {
if (grid.items[idx(pos.row - 1, pos.col - 1, col_count)]) {
surrounding += 1;
try append(&potential_changes, &potential_changes_len, Position{ .row = pos.row - 1, .col = pos.col - 1 });
}
}
if (grid.items[idx(pos.row - 1, pos.col, col_count)]) {
surrounding += 1;
try append(&potential_changes, &potential_changes_len, Position{ .row = pos.row - 1, .col = pos.col });
}
if (pos.col + 1 < col_count) {
if (grid.items[idx(pos.row - 1, pos.col + 1, col_count)]) {
surrounding += 1;
try append(&potential_changes, &potential_changes_len, Position{ .row = pos.row - 1, .col = pos.col + 1 });
}
}
}
if (pos.col > 0) {
if (grid.items[idx(pos.row, pos.col - 1, col_count)]) {
surrounding += 1;
try append(&potential_changes, &potential_changes_len, Position{ .row = pos.row, .col = pos.col - 1 });
}
}
if (pos.col + 1 < col_count) {
if (grid.items[idx(pos.row, pos.col + 1, col_count)]) {
surrounding += 1;
try append(&potential_changes, &potential_changes_len, Position{ .row = pos.row, .col = pos.col + 1 });
}
}
if (pos.row + 1 < row_count) {
if (pos.col > 0) {
if (grid.items[idx(pos.row + 1, pos.col - 1, col_count)]) {
surrounding += 1;
try append(&potential_changes, &potential_changes_len, Position{ .row = pos.row + 1, .col = pos.col - 1 });
}
}
if (grid.items[idx(pos.row + 1, pos.col, col_count)]) {
surrounding += 1;
try append(&potential_changes, &potential_changes_len, Position{ .row = pos.row + 1, .col = pos.col });
}
if (pos.col + 1 < col_count) {
if (grid.items[idx(pos.row + 1, pos.col + 1, col_count)]) {
surrounding += 1;
try append(&potential_changes, &potential_changes_len, Position{ .row = pos.row + 1, .col = pos.col + 1 });
}
}
}
if (surrounding < 4) {
accessible_rolls += 1;
next_grid.items[idx(pos.row, pos.col, col_count)] = false;
std.debug.print("(r:{}, c:{}) surrounding: {}", .{ pos.row, pos.col, surrounding });
const potential_changes_slice = potential_changes[0..potential_changes_len];
try changes.appendSlice(alloc, potential_changes_slice);
try seen.put(pos, true);
}
std.debug.print("\n", .{});
}
std.debug.print("\n rolls: {}\n\n", .{accessible_rolls});
if (changes.items.len == current_changes_len) {
changes_made = false;
}
current_head = current_changes_len;
@memcpy(grid.items, next_grid.items);
// return;
}
std.debug.print("accessible rolls: {}\n", .{accessible_rolls});
try day4.bufferedPrint();
}
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