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1 file changed, 184 insertions
aoc2015day14.zig(Datei erstellt)
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| 1 | + | const std = @import("std"); | |
| 2 | + | const mem = std.mem; | |
| 3 | + | const fs = std.fs; | |
| 4 | + | const print = std.debug.print; | |
| 5 | + | ||
| 6 | + | const ParseError = error{ | |
| 7 | + | RanOutOfWords, | |
| 8 | + | }; | |
| 9 | + | ||
| 10 | + | const Parser = struct { | |
| 11 | + | it: mem.SplitIterator(u8, .scalar), | |
| 12 | + | ||
| 13 | + | fn fromString(str: []const u8) Parser { | |
| 14 | + | return Parser{ | |
| 15 | + | .it = mem.splitScalar(u8, str, ' '), | |
| 16 | + | }; | |
| 17 | + | } | |
| 18 | + | ||
| 19 | + | fn take(self: *Parser) ![]const u8 { | |
| 20 | + | const wordo = self.it.next(); | |
| 21 | + | if (wordo) |word| { | |
| 22 | + | return word; | |
| 23 | + | } else { | |
| 24 | + | return ParseError.RanOutOfWords; | |
| 25 | + | } | |
| 26 | + | } | |
| 27 | + | ||
| 28 | + | fn skip(self: *Parser, cnt: usize) void { | |
| 29 | + | for (0..cnt) |_| { | |
| 30 | + | _ = self.it.next(); | |
| 31 | + | } | |
| 32 | + | } | |
| 33 | + | ||
| 34 | + | fn takeAsNumber(self: *Parser, Type: type) !Type { | |
| 35 | + | const wordo = self.it.next(); | |
| 36 | + | if (wordo) |word| { | |
| 37 | + | return std.fmt.parseInt(Type, word, 10); | |
| 38 | + | } else { | |
| 39 | + | return ParseError.RanOutOfWords; | |
| 40 | + | } | |
| 41 | + | } | |
| 42 | + | }; | |
| 43 | + | ||
| 44 | + | const Raindeer = struct { | |
| 45 | + | speed: usize, | |
| 46 | + | flight: usize, | |
| 47 | + | rest: usize, | |
| 48 | + | ||
| 49 | + | fn distanceAfter(self: Raindeer, sec: usize) usize { | |
| 50 | + | const chunk_time = self.flight + self.rest; | |
| 51 | + | const chunk_dist = self.speed * self.flight; | |
| 52 | + | const chunked = chunk_dist * (sec / chunk_time); | |
| 53 | + | const left = @mod(sec, chunk_time); | |
| 54 | + | const rest = if (left > self.flight) self.speed * self.flight else self.speed * left; | |
| 55 | + | return chunked + rest; | |
| 56 | + | } | |
| 57 | + | }; | |
| 58 | + | ||
| 59 | + | fn getLines(path: []const u8, alloc: mem.Allocator) !std.ArrayList(Raindeer) { | |
| 60 | + | const file = fs.cwd().openFile(path, .{}) catch |err| { | |
| 61 | + | std.log.err("Failed to open file {s}", .{@errorName(err)}); | |
| 62 | + | return err; | |
| 63 | + | }; | |
| 64 | + | defer file.close(); | |
| 65 | + | ||
| 66 | + | var raindeer = std.ArrayList(Raindeer).init(alloc); | |
| 67 | + | ||
| 68 | + | while (file.reader().readUntilDelimiterOrEofAlloc(alloc, '\n', std.math.maxInt(usize)) catch |err| { | |
| 69 | + | std.log.err("Failed to read line: {s}", .{@errorName(err)}); | |
| 70 | + | return err; | |
| 71 | + | }) |line| { | |
| 72 | + | defer alloc.free(line); | |
| 73 | + | var words = Parser.fromString(line); | |
| 74 | + | words.skip(3); | |
| 75 | + | const speed = try words.takeAsNumber(usize); | |
| 76 | + | words.skip(2); | |
| 77 | + | const flight = try words.takeAsNumber(usize); | |
| 78 | + | words.skip(6); | |
| 79 | + | const rest = try words.takeAsNumber(usize); | |
| 80 | + | try raindeer.append(.{ | |
| 81 | + | .speed = speed, | |
| 82 | + | .flight = flight, | |
| 83 | + | .rest = rest, | |
| 84 | + | }); | |
| 85 | + | } | |
| 86 | + | return raindeer; | |
| 87 | + | } | |
| 88 | + | ||
| 89 | + | fn part1(raindeer: std.ArrayList(Raindeer)) !void { | |
| 90 | + | var score: usize = 0; | |
| 91 | + | ||
| 92 | + | for (raindeer.items) |rd| { | |
| 93 | + | score = @max(score, rd.distanceAfter(2503)); | |
| 94 | + | } | |
| 95 | + | ||
| 96 | + | print("Part1: {d}\n", .{score}); | |
| 97 | + | } | |
| 98 | + | ||
| 99 | + | const RaindeerState = struct { | |
| 100 | + | raindeer: Raindeer, | |
| 101 | + | running: bool, | |
| 102 | + | time: usize, | |
| 103 | + | distance: usize, | |
| 104 | + | points: usize, | |
| 105 | + | ||
| 106 | + | fn fromRaindeer(rnd: Raindeer) RaindeerState { | |
| 107 | + | return .{ | |
| 108 | + | .raindeer = rnd, | |
| 109 | + | .running = true, | |
| 110 | + | .time = 0, | |
| 111 | + | .distance = 0, | |
| 112 | + | .points = 0, | |
| 113 | + | }; | |
| 114 | + | } | |
| 115 | + | ||
| 116 | + | fn tick(self: *RaindeerState) void { | |
| 117 | + | if (self.running) { | |
| 118 | + | self.distance += self.raindeer.speed; | |
| 119 | + | self.time += 1; | |
| 120 | + | if (self.time >= self.raindeer.flight) { | |
| 121 | + | self.time = 0; | |
| 122 | + | self.running = false; | |
| 123 | + | } | |
| 124 | + | } else { | |
| 125 | + | self.time += 1; | |
| 126 | + | if (self.time >= self.raindeer.rest) { | |
| 127 | + | self.time = 0; | |
| 128 | + | self.running = true; | |
| 129 | + | } | |
| 130 | + | } | |
| 131 | + | } | |
| 132 | + | }; | |
| 133 | + | ||
| 134 | + | fn run(raindeer: std.ArrayList(Raindeer), alloc: mem.Allocator, sec: usize) !usize { | |
| 135 | + | var states = std.ArrayList(*RaindeerState).init(alloc); | |
| 136 | + | defer { | |
| 137 | + | for (states.items) |state| { | |
| 138 | + | alloc.destroy(state); | |
| 139 | + | } | |
| 140 | + | states.deinit(); | |
| 141 | + | } | |
| 142 | + | ||
| 143 | + | for (raindeer.items) |rnd| { | |
| 144 | + | const state = try alloc.create(RaindeerState); | |
| 145 | + | state.* = RaindeerState.fromRaindeer(rnd); | |
| 146 | + | try states.append(state); | |
| 147 | + | } | |
| 148 | + | ||
| 149 | + | for (0..sec) |_| { | |
| 150 | + | var max_dist: usize = 0; | |
| 151 | + | for (states.items) |state| { | |
| 152 | + | state.tick(); | |
| 153 | + | max_dist = @max(max_dist, state.distance); | |
| 154 | + | } | |
| 155 | + | ||
| 156 | + | for (states.items) |state| { | |
| 157 | + | if (state.distance == max_dist) | |
| 158 | + | state.points += 1; | |
| 159 | + | } | |
| 160 | + | } | |
| 161 | + | var max_points: usize = 0; | |
| 162 | + | for (states.items) |state| { | |
| 163 | + | max_points = @max(max_points, state.points); | |
| 164 | + | } | |
| 165 | + | return max_points; | |
| 166 | + | } | |
| 167 | + | ||
| 168 | + | fn part2(raindeer: std.ArrayList(Raindeer), alloc: mem.Allocator) !void { | |
| 169 | + | const score = try run(raindeer, alloc, 2503); | |
| 170 | + | print("Part2: {d}\n", .{score}); | |
| 171 | + | } | |
| 172 | + | ||
| 173 | + | pub fn main() !void { | |
| 174 | + | var gpa = std.heap.GeneralPurposeAllocator(.{}){}; | |
| 175 | + | defer _ = gpa.deinit(); | |
| 176 | + | const alloc = gpa.allocator(); | |
| 177 | + | ||
| 178 | + | const filename = "day14.txt"; | |
| 179 | + | var raindeer = try getLines(filename, alloc); | |
| 180 | + | defer raindeer.deinit(); | |
| 181 | + | ||
| 182 | + | try part1(raindeer); | |
| 183 | + | try part2(raindeer, alloc); | |
| 184 | + | } | |
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