Finish day11, part 1

src/days/day11.zig

@@ -1,7 +1,79 @@
 const std = @import("std");
 
-pub const title = "Day 11";
+pub const title = "Day 11: Reactor";
 
-pub fn run(_: std.mem.Allocator) !void {
+pub fn run(allocator: std.mem.Allocator) !void {
+    const input = @embedFile("./input/day11.txt");
+    //const input =
+    //    \\aaa: you hhh
+    //    \\you: bbb ccc
+    //    \\bbb: ddd eee
+    //    \\ccc: ddd eee fff
+    //    \\ddd: ggg
+    //    \\eee: out
+    //    \\fff: out
+    //    \\ggg: out
+    //    \\hhh: ccc fff iii
+    //    \\iii: out
+    //    ;
+
+    var lines = std.mem.tokenizeScalar(u8, input, '\n');
+
+    var devices: std.StringHashMap([][]const u8) = .init(allocator);
+    defer {
+        var outputs_iter = devices.valueIterator();
+        while (outputs_iter.next()) |value| {
+            allocator.free(value.*);
+        }
+        devices.deinit();
+    }
+
+    while (lines.next()) |line| {
+        const device = line[0..3];
+        std.debug.print("device = {s}\n", .{device});
+
+        var outputs: std.ArrayList([]const u8) = .empty;
+        defer outputs.deinit(allocator);
+
+        var outputs_iter = std.mem.tokenizeScalar(u8, line[5..], ' ');
+        while (outputs_iter.next()) |output| {
+            try outputs.append(allocator, output);
+        }
+
+        const outputs_slice = try outputs.toOwnedSlice(allocator);
+        errdefer allocator.free(outputs_slice);
+
+        try devices.put(device, outputs_slice);
+    }
+
+    var paths_to_out: usize = 0;
+    visitOutputs("you", devices, &paths_to_out);
+
+    var buffer: [8]u8 = undefined;
+    var stdout_writer = std.fs.File.stdout().writer(&buffer);
+    const stdout = &stdout_writer.interface;
+
+    try stdout.print("{d}\n", .{paths_to_out});
+
+    try stdout.flush();
+}
+
+fn visitOutputs(
+    start: []const u8,
+    devices: std.StringHashMap([][]const u8),
+    paths_to_out: *usize,
+) void {
+    const device = devices.get(start);
+    if (device) |outputs| {
+        for (outputs) |output| {
+            if (std.mem.eql(u8, output, "out")) {
+                paths_to_out.* += 1;
+            } else {
+                visitOutputs(output, devices, paths_to_out);
+            }
+        }
+    } else {
+        std.debug.print("device {s} not found\n", .{start});
+    }
 }