Day 7.1

07/build.zig

@@ -0,0 +1,15 @@
+const Builder = @import("std").build.Builder;
+
+pub fn build(b: *Builder) void {
+    const mode = b.standardReleaseOptions();
+    const exe = b.addExecutable("07", "src/main.zig");
+    exe.addPackagePath("intcode", "../lib/intcode/intcode.zig");
+    exe.setBuildMode(mode);
+    exe.install();
+
+    const run_cmd = exe.run();
+    run_cmd.step.dependOn(b.getInstallStep());
+
+    const run_step = b.step("run", "Run the app");
+    run_step.dependOn(&run_cmd.step);
+}

07/input

@@ -0,0 +1 @@
+3,8,1001,8,10,8,105,1,0,0,21,34,55,68,85,106,187,268,349,430,99999,3,9,1001,9,5,9,1002,9,5,9,4,9,99,3,9,1002,9,2,9,1001,9,2,9,1002,9,5,9,1001,9,2,9,4,9,99,3,9,101,3,9,9,102,3,9,9,4,9,99,3,9,1002,9,5,9,101,3,9,9,102,5,9,9,4,9,99,3,9,1002,9,4,9,1001,9,2,9,102,3,9,9,101,3,9,9,4,9,99,3,9,1001,9,2,9,4,9,3,9,101,2,9,9,4,9,3,9,1002,9,2,9,4,9,3,9,1002,9,2,9,4,9,3,9,1001,9,1,9,4,9,3,9,1001,9,2,9,4,9,3,9,1002,9,2,9,4,9,3,9,101,2,9,9,4,9,3,9,1001,9,2,9,4,9,3,9,102,2,9,9,4,9,99,3,9,1002,9,2,9,4,9,3,9,102,2,9,9,4,9,3,9,101,1,9,9,4,9,3,9,1001,9,1,9,4,9,3,9,1001,9,1,9,4,9,3,9,101,1,9,9,4,9,3,9,1001,9,1,9,4,9,3,9,101,2,9,9,4,9,3,9,1001,9,1,9,4,9,3,9,1001,9,1,9,4,9,99,3,9,1001,9,2,9,4,9,3,9,101,2,9,9,4,9,3,9,101,2,9,9,4,9,3,9,1002,9,2,9,4,9,3,9,102,2,9,9,4,9,3,9,1002,9,2,9,4,9,3,9,101,1,9,9,4,9,3,9,1002,9,2,9,4,9,3,9,102,2,9,9,4,9,3,9,1002,9,2,9,4,9,99,3,9,102,2,9,9,4,9,3,9,1001,9,2,9,4,9,3,9,102,2,9,9,4,9,3,9,102,2,9,9,4,9,3,9,101,1,9,9,4,9,3,9,102,2,9,9,4,9,3,9,102,2,9,9,4,9,3,9,102,2,9,9,4,9,3,9,101,1,9,9,4,9,3,9,1002,9,2,9,4,9,99,3,9,102,2,9,9,4,9,3,9,1001,9,1,9,4,9,3,9,102,2,9,9,4,9,3,9,101,1,9,9,4,9,3,9,102,2,9,9,4,9,3,9,102,2,9,9,4,9,3,9,101,2,9,9,4,9,3,9,101,2,9,9,4,9,3,9,1001,9,2,9,4,9,3,9,102,2,9,9,4,9,99

07/src/main.zig

@@ -0,0 +1,178 @@
+const std = @import("std");
+
+const intcode = @import("intcode");
+
+// TODO: it would be awesome if we could make this a comptime function
+const permutations = [120][5]i32{
+    .{ 0, 1, 2, 3, 4 },
+    .{ 0, 1, 2, 4, 3 },
+    .{ 0, 1, 3, 2, 4 },
+    .{ 0, 1, 3, 4, 2 },
+    .{ 0, 1, 4, 2, 3 },
+    .{ 0, 1, 4, 3, 2 },
+    .{ 0, 2, 1, 3, 4 },
+    .{ 0, 2, 1, 4, 3 },
+    .{ 0, 2, 3, 1, 4 },
+    .{ 0, 2, 3, 4, 1 },
+    .{ 0, 2, 4, 1, 3 },
+    .{ 0, 2, 4, 3, 1 },
+    .{ 0, 3, 1, 2, 4 },
+    .{ 0, 3, 1, 4, 2 },
+    .{ 0, 3, 2, 1, 4 },
+    .{ 0, 3, 2, 4, 1 },
+    .{ 0, 3, 4, 1, 2 },
+    .{ 0, 3, 4, 2, 1 },
+    .{ 0, 4, 1, 2, 3 },
+    .{ 0, 4, 1, 3, 2 },
+    .{ 0, 4, 2, 1, 3 },
+    .{ 0, 4, 2, 3, 1 },
+    .{ 0, 4, 3, 1, 2 },
+    .{ 0, 4, 3, 2, 1 },
+    .{ 1, 0, 2, 3, 4 },
+    .{ 1, 0, 2, 4, 3 },
+    .{ 1, 0, 3, 2, 4 },
+    .{ 1, 0, 3, 4, 2 },
+    .{ 1, 0, 4, 2, 3 },
+    .{ 1, 0, 4, 3, 2 },
+    .{ 1, 2, 0, 3, 4 },
+    .{ 1, 2, 0, 4, 3 },
+    .{ 1, 2, 3, 0, 4 },
+    .{ 1, 2, 3, 4, 0 },
+    .{ 1, 2, 4, 0, 3 },
+    .{ 1, 2, 4, 3, 0 },
+    .{ 1, 3, 0, 2, 4 },
+    .{ 1, 3, 0, 4, 2 },
+    .{ 1, 3, 2, 0, 4 },
+    .{ 1, 3, 2, 4, 0 },
+    .{ 1, 3, 4, 0, 2 },
+    .{ 1, 3, 4, 2, 0 },
+    .{ 1, 4, 0, 2, 3 },
+    .{ 1, 4, 0, 3, 2 },
+    .{ 1, 4, 2, 0, 3 },
+    .{ 1, 4, 2, 3, 0 },
+    .{ 1, 4, 3, 0, 2 },
+    .{ 1, 4, 3, 2, 0 },
+    .{ 2, 0, 1, 3, 4 },
+    .{ 2, 0, 1, 4, 3 },
+    .{ 2, 0, 3, 1, 4 },
+    .{ 2, 0, 3, 4, 1 },
+    .{ 2, 0, 4, 1, 3 },
+    .{ 2, 0, 4, 3, 1 },
+    .{ 2, 1, 0, 3, 4 },
+    .{ 2, 1, 0, 4, 3 },
+    .{ 2, 1, 3, 0, 4 },
+    .{ 2, 1, 3, 4, 0 },
+    .{ 2, 1, 4, 0, 3 },
+    .{ 2, 1, 4, 3, 0 },
+    .{ 2, 3, 0, 1, 4 },
+    .{ 2, 3, 0, 4, 1 },
+    .{ 2, 3, 1, 0, 4 },
+    .{ 2, 3, 1, 4, 0 },
+    .{ 2, 3, 4, 0, 1 },
+    .{ 2, 3, 4, 1, 0 },
+    .{ 2, 4, 0, 1, 3 },
+    .{ 2, 4, 0, 3, 1 },
+    .{ 2, 4, 1, 0, 3 },
+    .{ 2, 4, 1, 3, 0 },
+    .{ 2, 4, 3, 0, 1 },
+    .{ 2, 4, 3, 1, 0 },
+    .{ 3, 0, 1, 2, 4 },
+    .{ 3, 0, 1, 4, 2 },
+    .{ 3, 0, 2, 1, 4 },
+    .{ 3, 0, 2, 4, 1 },
+    .{ 3, 0, 4, 1, 2 },
+    .{ 3, 0, 4, 2, 1 },
+    .{ 3, 1, 0, 2, 4 },
+    .{ 3, 1, 0, 4, 2 },
+    .{ 3, 1, 2, 0, 4 },
+    .{ 3, 1, 2, 4, 0 },
+    .{ 3, 1, 4, 0, 2 },
+    .{ 3, 1, 4, 2, 0 },
+    .{ 3, 2, 0, 1, 4 },
+    .{ 3, 2, 0, 4, 1 },
+    .{ 3, 2, 1, 0, 4 },
+    .{ 3, 2, 1, 4, 0 },
+    .{ 3, 2, 4, 0, 1 },
+    .{ 3, 2, 4, 1, 0 },
+    .{ 3, 4, 0, 1, 2 },
+    .{ 3, 4, 0, 2, 1 },
+    .{ 3, 4, 1, 0, 2 },
+    .{ 3, 4, 1, 2, 0 },
+    .{ 3, 4, 2, 0, 1 },
+    .{ 3, 4, 2, 1, 0 },
+    .{ 4, 0, 1, 2, 3 },
+    .{ 4, 0, 1, 3, 2 },
+    .{ 4, 0, 2, 1, 3 },
+    .{ 4, 0, 2, 3, 1 },
+    .{ 4, 0, 3, 1, 2 },
+    .{ 4, 0, 3, 2, 1 },
+    .{ 4, 1, 0, 2, 3 },
+    .{ 4, 1, 0, 3, 2 },
+    .{ 4, 1, 2, 0, 3 },
+    .{ 4, 1, 2, 3, 0 },
+    .{ 4, 1, 3, 0, 2 },
+    .{ 4, 1, 3, 2, 0 },
+    .{ 4, 2, 0, 1, 3 },
+    .{ 4, 2, 0, 3, 1 },
+    .{ 4, 2, 1, 0, 3 },
+    .{ 4, 2, 1, 3, 0 },
+    .{ 4, 2, 3, 0, 1 },
+    .{ 4, 2, 3, 1, 0 },
+    .{ 4, 3, 0, 1, 2 },
+    .{ 4, 3, 0, 2, 1 },
+    .{ 4, 3, 1, 0, 2 },
+    .{ 4, 3, 1, 2, 0 },
+    .{ 4, 3, 2, 0, 1 },
+    .{ 4, 3, 2, 1, 0 },
+};
+
+pub fn main() anyerror!void {
+    var arena = std.heap.ArenaAllocator.init(std.heap.page_allocator);
+    defer arena.deinit();
+
+    const alloc = &arena.allocator;
+    var program = try intcode.loadFromStdIn(alloc);
+
+    // 5 intcode computers act as the amps
+    var machines: [5]intcode.Machine = undefined;
+
+    // 120 phase permutations. Find the highest.
+    var max: i32 = 0;
+    for (permutations) |inputs| {
+        for (machines) |*machine| {
+            var copy = try alloc.alloc(i32, program.len);
+            std.mem.copy(i32, copy, program);
+
+            machine.* = try intcode.Machine.init(alloc, copy);
+        }
+
+        // Phase input
+        for (inputs) |input, i| {
+            try machines[i].input.append(input);
+        }
+
+        // amplifier input
+        for (machines) |*machine, i| {
+            var ampInput: i32 = 0;
+            if (i > 0) {
+                try machine.input.append(machines[i - 1].output.at(0));
+            } else {
+                try machine.input.append(0);
+            }
+
+            try machine.run();
+        }
+
+        const final = machines[4].output.at(0);
+        if (final > max)
+            max = final;
+
+        // Don't forget to free everything!
+        for (machines) |*machine, i| {
+            alloc.free(machine.memory);
+            machine.deinit();
+        }
+    }
+
+    std.debug.warn("Part 1: {}\n", max);
+}

lib/intcode/intcode.zig

@@ -13,7 +13,7 @@ pub fn loadFromStream(alloc: *std.mem.Allocator, stream: *std.fs.File.InStream.S
         var trimmed = std.mem.trimRight(u8, num, "\r\n");
         program[i] = try std.fmt.parseInt(i32, trimmed, 10);
 
-        std.debug.warn("{},", program[i]);
+        //        std.debug.warn("{},", program[i]);
 
         i += 1;
     }
@@ -118,6 +118,11 @@ pub const Machine = struct {
         while (try self.step()) {}
     }
 
+    pub fn deinit(self: *Machine) void {
+        self.input.deinit();
+        self.output.deinit();
+    }
+
     /// Read an immediate or position value from memory. Parameter determines
     /// which field following the current instruction to read from
     inline fn __read(self: *Machine, parameter: usize, mode: Mode) i32 {

run-intcodes

@@ -2,3 +2,4 @@
 zig test lib/intcode/intcode.zig
 zig build --build-file 02/build.zig run < 02/input
 zig build --build-file 05/build.zig run < 05/input
+zig build --build-file 07/build.zig run < 07/input