Day 18, lets go!
This commit is contained in:
239
AdventOfCode2023/src/day16/day16.zig
Normal file
239
AdventOfCode2023/src/day16/day16.zig
Normal file
@ -0,0 +1,239 @@
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const std = @import("std");
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const print = std.debug.print;
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const EMPTY = '.';
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const VERTICAL_SPLIT = '|';
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const HORIZONTAL_SPLIT = '-';
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const CLOCKWISE_TURN = '/';
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const ANTI_CLOCKWISE_TURN = '\\';
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const Directions = enum { UP, DOWN, LEFT, RIGHT };
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const BeamsController = struct {
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beams: std.AutoHashMap(usize, *Beam),
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allocator: std.mem.Allocator,
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counter: usize,
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heatmap: std.AutoHashMap(u128, bool),
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splitsMade: std.AutoHashMap(u128, bool),
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pub fn walk(self: *BeamsController) !void {
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var iter = self.*.beams.iterator();
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var deleteList = std.ArrayList(usize).init(self.allocator);
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defer deleteList.deinit();
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while (iter.next()) |entry| {
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var delete = try entry.value_ptr.*.step();
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if (delete) {
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// print("Beam {} removing\n", .{entry.value_ptr.*.index});
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try deleteList.append(entry.key_ptr.*);
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// self.allocator.destroy(entry.value_ptr.*);
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} else {
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// var beams = entry.value_ptr.*;
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// print("Beam {} ({},{}) {}\n", .{ beams.index, beams.x, beams.y, beams.direction });
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}
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}
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for (deleteList.items) |i| {
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_ = self.*.beams.remove(i);
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}
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}
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pub fn horizontalSplit(self: *BeamsController, beam: *Beam) !bool {
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// Assume direction is up or down.
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// Assume "parent" beam always goes right.
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var coord = @as(u128, beam.x) << 64 | @as(u128, beam.y);
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if (self.*.splitsMade.get(coord)) |_| {
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// dont split again
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return true;
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}
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var splitBeam = try self.allocator.create(Beam);
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splitBeam.*.grid = beam.*.grid;
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splitBeam.*.x = beam.*.x;
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splitBeam.*.y = beam.*.y;
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splitBeam.*.direction = Directions.LEFT;
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splitBeam.*.controller = beam.*.controller;
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self.*.counter += 1;
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splitBeam.*.index = self.*.counter;
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try self.*.beams.put(splitBeam.index, splitBeam);
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try self.*.splitsMade.put(coord, true);
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return false;
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}
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pub fn verticalSplit(self: *BeamsController, beam: *Beam) !bool {
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// Assume direction is left or right
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// Assume "parent" beam always goes down.
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var coord = @as(u128, beam.x) << 64 | @as(u128, beam.y);
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if (self.*.splitsMade.get(coord)) |_| {
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// dont split again
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return true;
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}
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var splitBeam = try self.allocator.create(Beam);
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splitBeam.*.grid = beam.*.grid;
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splitBeam.*.x = beam.*.x;
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splitBeam.*.y = beam.*.y;
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splitBeam.*.direction = Directions.UP;
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splitBeam.*.controller = beam.*.controller;
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self.*.counter += 1;
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splitBeam.*.index = self.*.counter;
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try self.*.beams.put(splitBeam.index, splitBeam);
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try self.*.splitsMade.put(coord, true);
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return false;
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}
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};
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const Beam = struct {
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grid: *[][]const u8,
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x: usize,
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y: usize,
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direction: Directions,
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controller: *BeamsController,
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index: usize,
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pub fn step(self: *Beam) !bool {
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var coord = @as(u128, self.x) << 64 | @as(u128, self.y);
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try self.*.controller.heatmap.put(coord, true);
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switch (self.direction) {
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Directions.RIGHT => {
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if (self.*.x == self.*.grid.*[0].len - 1) {
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return true;
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}
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var tile = self.*.grid.*[self.*.y][self.*.x];
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if (tile == VERTICAL_SPLIT) {
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// call beams controller vertical split.
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var alreadyDone = try self.controller.verticalSplit(self);
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if (alreadyDone) {
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return true;
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}
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self.*.direction = Directions.DOWN;
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} else if (tile == CLOCKWISE_TURN) {
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// moving right. turn upwards.
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self.*.direction = Directions.UP;
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} else if (tile == ANTI_CLOCKWISE_TURN) {
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self.*.direction = Directions.DOWN;
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}
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},
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Directions.LEFT => {
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if (self.*.x == 0) {
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return true;
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}
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var tile = self.*.grid.*[self.*.y][self.*.x];
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if (tile == VERTICAL_SPLIT) {
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// call beams controller vertical split.
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var alreadyDone = try self.controller.verticalSplit(self);
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if (alreadyDone) {
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return true;
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}
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self.*.direction = Directions.DOWN;
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} else if (tile == CLOCKWISE_TURN) {
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// moving right. turn upwards.
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self.*.direction = Directions.DOWN;
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} else if (tile == ANTI_CLOCKWISE_TURN) {
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self.*.direction = Directions.UP;
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}
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},
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Directions.UP => {
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if (self.*.y == 0) {
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return true;
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}
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var tile = self.*.grid.*[self.*.y][self.*.x];
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if (tile == HORIZONTAL_SPLIT) {
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// call beams controller vertical split.
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var alreadyDone = try self.controller.horizontalSplit(self);
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if (alreadyDone) {
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return true;
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}
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self.*.direction = Directions.RIGHT;
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} else if (tile == CLOCKWISE_TURN) {
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// moving right. turn upwards.
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self.*.direction = Directions.RIGHT;
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} else if (tile == ANTI_CLOCKWISE_TURN) {
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self.*.direction = Directions.LEFT;
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}
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},
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Directions.DOWN => {
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if (self.*.y == self.*.grid.*.len - 1) {
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return true;
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}
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var tile = self.*.grid.*[self.*.y][self.*.x];
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if (tile == HORIZONTAL_SPLIT) {
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// call beams controller vertical split.
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var alreadyDone = try self.controller.horizontalSplit(self);
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if (alreadyDone) {
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return true;
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}
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self.*.direction = Directions.RIGHT;
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} else if (tile == CLOCKWISE_TURN) {
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// moving right. turn upwards.
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self.*.direction = Directions.LEFT;
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} else if (tile == ANTI_CLOCKWISE_TURN) {
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self.*.direction = Directions.RIGHT;
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}
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},
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}
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switch (self.direction) {
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Directions.UP => {
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self.*.y -= 1;
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},
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Directions.DOWN => {
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self.*.y += 1;
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},
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Directions.LEFT => {
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self.*.x -= 1;
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},
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Directions.RIGHT => {
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self.*.x += 1;
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},
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}
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coord = @as(u128, self.x) << 64 | @as(u128, self.y);
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try self.*.controller.heatmap.put(coord, true);
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return false;
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}
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};
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pub fn solve(input: [][]const u8) !void {
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var allocator = std.heap.page_allocator;
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var controller = BeamsController{ .allocator = allocator, .beams = std.AutoHashMap(usize, *Beam).init(allocator), .counter = 0, .heatmap = std.AutoHashMap(u128, bool).init(allocator), .splitsMade = std.AutoHashMap(u128, bool).init(allocator) };
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var in = input;
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var firstBeam = try allocator.create(Beam);
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firstBeam.*.x = 0;
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firstBeam.*.y = 0;
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firstBeam.*.direction = Directions.RIGHT;
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firstBeam.*.grid = ∈
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firstBeam.*.controller = &controller;
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firstBeam.*.index = 0;
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try controller.beams.put(0, firstBeam);
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while (controller.beams.count() > 0) {
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try controller.walk();
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}
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var iter = controller.heatmap.iterator();
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while (iter.next()) |entry| {
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var x = entry.key_ptr.* >> 64;
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var y = entry.key_ptr.* & 0xFFFFFFFFFFFFFFFF;
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print("{},{}\n", .{ x, y });
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}
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print("Part 1: {}\n", .{controller.heatmap.count()});
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}
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// 6858
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159
AdventOfCode2023/src/day18/day18.zig
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159
AdventOfCode2023/src/day18/day18.zig
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@ -0,0 +1,159 @@
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const std = @import("std");
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const print = std.debug.print;
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const GRID_SIZE = 10000;
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fn countInside(grid: *[][]u32, x: usize, y: usize) void {
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if (grid.*[y][x] == 1) {
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return;
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}
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if (grid.*[y][x] > 2) {
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return;
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}
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grid.*[y][x] = 1;
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countInside(grid, x - 1, y);
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countInside(grid, x + 1, y);
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countInside(grid, x, y - 1);
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countInside(grid, x, y + 1);
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countInside(grid, x - 1, y - 1);
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countInside(grid, x + 1, y - 1);
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countInside(grid, x + 1, y + 1);
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countInside(grid, x - 1, y + 1);
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}
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pub fn solve(input: [][]const u8) !void {
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const allocator = std.heap.page_allocator;
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var grid = try allocator.alloc([]u32, GRID_SIZE);
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for (0..grid.len) |i| {
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grid[i] = try allocator.alloc(u32, GRID_SIZE);
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@memset(grid[i], 2);
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}
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var coords = std.ArrayList(u128).init(allocator);
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var x: usize = GRID_SIZE / 2;
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var y: usize = GRID_SIZE / 2;
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var part2x: usize = 20_000_000_000;
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var part2y: usize = 20_000_000_000;
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var part2edges: usize = 0;
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for (input) |line| {
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var tokenizer = std.mem.tokenizeSequence(u8, line, " ");
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var stringDirection = tokenizer.next().?;
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var times = try std.fmt.parseInt(u32, tokenizer.next().?, 10);
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var stringColour = tokenizer.next().?;
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var colour = try std.fmt.parseInt(u32, stringColour[2 .. stringColour.len - 2], 16);
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for (0..times) |_| {
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switch (stringDirection[0]) {
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'U' => {
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y -= 1;
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},
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'D' => {
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y += 1;
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},
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'R' => {
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x += 1;
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},
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'L' => {
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x -= 1;
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},
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else => unreachable,
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}
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grid[y][x] = colour;
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}
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var part2Direction = stringColour[stringColour.len - 2 .. stringColour.len - 1][0] - '0';
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part2edges += colour;
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if (part2Direction == 0) {
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// Right
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var c2 = @as(u128, part2x + colour) << 64 | @as(u128, part2y);
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part2x = part2x + colour;
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// try coords.put(c1, true);
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try coords.append(c2);
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} else if (part2Direction == 1) {
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// Down
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var c2 = @as(u128, part2x) << 64 | @as(u128, part2y + colour);
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part2y = part2y + colour;
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// try coords.put(c1, true);
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try coords.append(c2);
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} else if (part2Direction == 2) {
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// Left
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var c2 = @as(u128, part2x - colour) << 64 | @as(u128, part2y);
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part2x = part2x - colour;
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// try coords.put(c1, true);
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try coords.append(c2);
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} else if (part2Direction == 3) {
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// Up
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var c2 = @as(u128, part2x) << 64 | @as(u128, part2y - colour);
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part2y = part2y - colour;
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// try coords.put(c1, true);
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try coords.append(c2);
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}
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}
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countInside(&grid, GRID_SIZE / 2 + 1, GRID_SIZE / 2 + 1);
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var part1: usize = 0;
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var part2: i256 = 0;
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for (4800..5300) |i| {
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for (4800..5300) |j| {
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if (grid[i][j] == 2) {
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// print(".", .{});
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} else {
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// print("#", .{});
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part1 += 1;
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}
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}
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// print("\n", .{});
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}
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var first = coords.items[0];
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var prev = first;
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var items = try coords.toOwnedSlice();
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for (items) |key| {
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var x2 = @as(i256, key >> 64);
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var y2 = @as(i256, key & 0xFFFFFFFFFFFFFFFF);
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var x1 = @as(i256, prev >> 64);
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var y1 = @as(i256, prev & 0xFFFFFFFFFFFFFFFF);
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prev = key;
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part2 += x1 * y2 - x2 * y1;
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}
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var x2 = @as(i256, first >> 64);
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var y2 = @as(i256, first & 0xFFFFFFFFFFFFFFFF);
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var x1 = @as(i256, prev >> 64);
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var y1 = @as(i256, prev & 0xFFFFFFFFFFFFFFFF);
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part2 += x1 * y2 - x2 * y1;
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part2 = @divTrunc(part2, 2);
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part2 += part2edges / 2 + 1;
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print("Part 1: {}\n", .{part1});
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print("Part 2: {}\n", .{part2});
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}
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@ -10,13 +10,15 @@ const std = @import("std");
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// const day10 = @import("./day10/day10.zig");
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// const day11 = @import("./day11/day11.zig");
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// const day12 = @import("./day12/day12.zig");
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const day15 = @import("./day15/day15.zig");
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// const day15 = @import("./day15/day15.zig");
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// const day16 = @import("./day16/day16.zig");
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const day18 = @import("./day18/day18.zig");
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const utils = @import("utils.zig");
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pub fn main() !void {
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const allocator = std.heap.page_allocator;
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var input = try utils.getInput("./src/day15/input.txt", allocator);
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var input = try utils.getInput("./src/day18/input.txt", allocator);
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defer allocator.free(input);
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try day15.solve(input);
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try day18.solve(input);
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}
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Reference in New Issue
Block a user