From a56453523dd1d49a0cd842db85cda7248512397b Mon Sep 17 00:00:00 2001 From: Julien Dessaux Date: Thu, 22 Dec 2022 09:55:35 +0100 Subject: 2022-14 in zig --- 2022/14-regolith-reservoir/first.zig | 194 +++++++++++++++++++++++++++++++++++ 1 file changed, 194 insertions(+) create mode 100644 2022/14-regolith-reservoir/first.zig (limited to '2022/14-regolith-reservoir/first.zig') diff --git a/2022/14-regolith-reservoir/first.zig b/2022/14-regolith-reservoir/first.zig new file mode 100644 index 0000000..d85ca23 --- /dev/null +++ b/2022/14-regolith-reservoir/first.zig @@ -0,0 +1,194 @@ +const std = @import("std"); + +const example = @embedFile("example"); +const input = @embedFile("input"); + +var allocator: std.mem.Allocator = undefined; + +pub fn main() anyerror!void { + var arena = std.heap.ArenaAllocator.init(std.heap.page_allocator); + defer arena.deinit(); + allocator = arena.allocator(); + + try std.testing.expectEqual(try solve(example), 24); + const result = try solve(input); + try std.io.getStdOut().writer().print("{}\n", .{result}); +} + +const Line = struct { + data: std.ArrayList(u8), + x: u64, + fn get(l: *Line, x: u64) u8 { + if (x >= l.x and x < l.x + @intCast(u64, l.len())) return l.data.items[@intCast(usize, x - @intCast(u64, l.x))]; + return ' '; + } + fn init() !*Line { + var l = try allocator.create(Line); + l.data = std.ArrayList(u8).init(allocator); + return l; + } + inline fn len(l: Line) usize { + return l.data.items.len; + } + fn set(l: *Line, x: u64, v: u8) !void { + if (l.len() == 0) { // this is en empty line + l.x = x; + try l.data.append(v); + return; + } + const lx = @intCast(u64, l.len()); + if (x >= l.x) { + if (x < l.x + lx) { // just set the value + l.data.items[@intCast(usize, x - l.x)] = v; + } else { // we need to add trailing spaces + var i: usize = l.len(); + while (i < x - l.x) : (i += 1) { + try l.data.append(' '); + } + try l.data.append(v); + } + } else { // we need to shift right and add leading spaces + const oldLen = l.len(); + l.data.items.len += @intCast(usize, l.x - x); + try l.data.ensureUnusedCapacity(l.len()); + std.mem.copyBackwards(u8, l.data.items[@intCast(usize, l.x - x)..], l.data.items[0..oldLen]); + l.data.items[0] = v; + var i: usize = 1; + while (i < @intCast(usize, l.x - x)) : (i += 1) { + l.data.items[i] = ' '; + } + l.x = x; + } + } +}; + +pub const Field = struct { + x: u64 = 0, + y: u64 = 0, + lines: std.ArrayList(*Line), + lx: usize = 0, + pub fn get(f: *Field, x: u64, y: u64) u8 { + if (y >= f.y and y < f.y + @intCast(u64, f.lines.items.len)) return f.lines.items[@intCast(usize, y - @intCast(u64, f.y))].get(x); + return ' '; + } + fn init() !*Field { + var f = try allocator.create(Field); + f.x = undefined; + f.y = 0; + f.lines = std.ArrayList(*Line).init(allocator); + var l = try f.lines.addOne(); + l.* = try Line.init(); + f.lx = 0; + return f; + } + inline fn isIn(f: *Field, x: u64, y: u64) bool { + return x >= f.x and y >= f.y and x < f.x + @intCast(u64, f.lx) and y < f.y + @intCast(u64, f.lines.items.len); + } + inline fn len(f: Field) usize { + return f.lines.items.len; + } + pub fn set(f: *Field, x: u64, y: u64, v: u8) !void { + if (y >= f.y) { + if (y < f.y + @intCast(u64, f.lines.items.len)) { // the line exists + try f.lines.items[@intCast(usize, y - f.y)].set(x, v); + } else { // append lines + var i: usize = f.lines.items.len; + while (i < y - f.y) : (i += 1) { + try f.lines.append(try Line.init()); + } + var l = try Line.init(); + try l.set(x, v); + try f.lines.append(l); + } + } else { // preprend lines + const oldLen = f.lines.items.len; + f.lines.items.len += @intCast(usize, f.y - y); + try f.lines.ensureUnusedCapacity(f.lines.items.len); + std.mem.copyBackwards(*Line, f.lines.items[@intCast(usize, f.y - y)..], f.lines.items[0..oldLen]); + var l = try Line.init(); + try l.set(x, v); + f.lines.items[0] = l; + var i: usize = 1; + while (i < @intCast(usize, f.y - y)) : (i += 1) { + f.lines.items[i] = try Line.init(); + } + f.y = y; + } + if (x < f.x or x >= f.x + @intCast(u64, f.lx)) { // recalculate boundaries + f.x = std.math.maxInt(u64); + var x2: u64 = std.math.minInt(u64); + for (f.lines.items) |line| { + if (line.len() == 0) continue; + if (f.x > line.x) f.x = line.x; + if (x2 < line.x + @intCast(u64, line.len())) x2 = line.x + @intCast(u64, line.len()); + } + f.lx = @intCast(usize, x2 - f.x); + } + return; + } +}; + +fn solve(puzzle: []const u8) !u64 { + var it = std.mem.tokenize(u8, puzzle, "\n"); + var field = try Field.init(); + // process input + while (it.next()) |line| { + var coords = std.mem.tokenize(u8, line, " ->,"); + var x = try std.fmt.parseInt(u64, coords.next() orelse continue, 10); + var y = try std.fmt.parseInt(u64, coords.next() orelse unreachable, 10); + try field.set(x, y, '#'); + while (true) { + var a = try std.fmt.parseInt(u64, coords.next() orelse break, 10); + var b = try std.fmt.parseInt(u64, coords.next() orelse unreachable, 10); + + while (x != a or y != b) { + if (x < a) { + x += 1; + } else if (x > a) { + x -= 1; + } + if (y < b) { + y += 1; + } else if (y > b) { + y -= 1; + } + try field.set(x, y, '#'); + } + } + } + // run simulation + var i: usize = 0; + outer: while (true) : (i += 1) { // add sand forever + var x: u64 = 500; + var y: u64 = field.y; + while (true) { // let the sand fall + if (!field.isIn(x, y)) { + break :outer; + } + switch (field.get(x, y + 1)) { + ' ' => y += 1, // we can fall straight down + else => { + switch (field.get(x - 1, y + 1)) { + ' ' => { // we can fall down to the left + x -= 1; + y += 1; + }, + else => { + switch (field.get(x + 1, y + 1)) { + ' ' => { // we can fall down to the right + x += 1; + y += 1; + }, + else => { // we stop falling + try field.set(x, y, 'o'); + break; + }, + } + }, + } + }, + } + } + } + return i; +} -- cgit v1.2.3