Day 7.2 using threads

07/src/main.zig

@@ -126,6 +126,175 @@ const perm1 = [120][5]i32{
     .{ 4, 3, 2, 1, 0 },
 };
 
+const perm2 = [120][5]i32{
+    .{ 5, 6, 7, 8, 9 },
+    .{ 5, 6, 7, 9, 8 },
+    .{ 5, 6, 8, 7, 9 },
+    .{ 5, 6, 8, 9, 7 },
+    .{ 5, 6, 9, 7, 8 },
+    .{ 5, 6, 9, 8, 7 },
+    .{ 5, 7, 6, 8, 9 },
+    .{ 5, 7, 6, 9, 8 },
+    .{ 5, 7, 8, 6, 9 },
+    .{ 5, 7, 8, 9, 6 },
+    .{ 5, 7, 9, 6, 8 },
+    .{ 5, 7, 9, 8, 6 },
+    .{ 5, 8, 6, 7, 9 },
+    .{ 5, 8, 6, 9, 7 },
+    .{ 5, 8, 7, 6, 9 },
+    .{ 5, 8, 7, 9, 6 },
+    .{ 5, 8, 9, 6, 7 },
+    .{ 5, 8, 9, 7, 6 },
+    .{ 5, 9, 6, 7, 8 },
+    .{ 5, 9, 6, 8, 7 },
+    .{ 5, 9, 7, 6, 8 },
+    .{ 5, 9, 7, 8, 6 },
+    .{ 5, 9, 8, 6, 7 },
+    .{ 5, 9, 8, 7, 6 },
+    .{ 6, 5, 7, 8, 9 },
+    .{ 6, 5, 7, 9, 8 },
+    .{ 6, 5, 8, 7, 9 },
+    .{ 6, 5, 8, 9, 7 },
+    .{ 6, 5, 9, 7, 8 },
+    .{ 6, 5, 9, 8, 7 },
+    .{ 6, 7, 5, 8, 9 },
+    .{ 6, 7, 5, 9, 8 },
+    .{ 6, 7, 8, 5, 9 },
+    .{ 6, 7, 8, 9, 5 },
+    .{ 6, 7, 9, 5, 8 },
+    .{ 6, 7, 9, 8, 5 },
+    .{ 6, 8, 5, 7, 9 },
+    .{ 6, 8, 5, 9, 7 },
+    .{ 6, 8, 7, 5, 9 },
+    .{ 6, 8, 7, 9, 5 },
+    .{ 6, 8, 9, 5, 7 },
+    .{ 6, 8, 9, 7, 5 },
+    .{ 6, 9, 5, 7, 8 },
+    .{ 6, 9, 5, 8, 7 },
+    .{ 6, 9, 7, 5, 8 },
+    .{ 6, 9, 7, 8, 5 },
+    .{ 6, 9, 8, 5, 7 },
+    .{ 6, 9, 8, 7, 5 },
+    .{ 7, 5, 6, 8, 9 },
+    .{ 7, 5, 6, 9, 8 },
+    .{ 7, 5, 8, 6, 9 },
+    .{ 7, 5, 8, 9, 6 },
+    .{ 7, 5, 9, 6, 8 },
+    .{ 7, 5, 9, 8, 6 },
+    .{ 7, 6, 5, 8, 9 },
+    .{ 7, 6, 5, 9, 8 },
+    .{ 7, 6, 8, 5, 9 },
+    .{ 7, 6, 8, 9, 5 },
+    .{ 7, 6, 9, 5, 8 },
+    .{ 7, 6, 9, 8, 5 },
+    .{ 7, 8, 5, 6, 9 },
+    .{ 7, 8, 5, 9, 6 },
+    .{ 7, 8, 6, 5, 9 },
+    .{ 7, 8, 6, 9, 5 },
+    .{ 7, 8, 9, 5, 6 },
+    .{ 7, 8, 9, 6, 5 },
+    .{ 7, 9, 5, 6, 8 },
+    .{ 7, 9, 5, 8, 6 },
+    .{ 7, 9, 6, 5, 8 },
+    .{ 7, 9, 6, 8, 5 },
+    .{ 7, 9, 8, 5, 6 },
+    .{ 7, 9, 8, 6, 5 },
+    .{ 8, 5, 6, 7, 9 },
+    .{ 8, 5, 6, 9, 7 },
+    .{ 8, 5, 7, 6, 9 },
+    .{ 8, 5, 7, 9, 6 },
+    .{ 8, 5, 9, 6, 7 },
+    .{ 8, 5, 9, 7, 6 },
+    .{ 8, 6, 5, 7, 9 },
+    .{ 8, 6, 5, 9, 7 },
+    .{ 8, 6, 7, 5, 9 },
+    .{ 8, 6, 7, 9, 5 },
+    .{ 8, 6, 9, 5, 7 },
+    .{ 8, 6, 9, 7, 5 },
+    .{ 8, 7, 5, 6, 9 },
+    .{ 8, 7, 5, 9, 6 },
+    .{ 8, 7, 6, 5, 9 },
+    .{ 8, 7, 6, 9, 5 },
+    .{ 8, 7, 9, 5, 6 },
+    .{ 8, 7, 9, 6, 5 },
+    .{ 8, 9, 5, 6, 7 },
+    .{ 8, 9, 5, 7, 6 },
+    .{ 8, 9, 6, 5, 7 },
+    .{ 8, 9, 6, 7, 5 },
+    .{ 8, 9, 7, 5, 6 },
+    .{ 8, 9, 7, 6, 5 },
+    .{ 9, 5, 6, 7, 8 },
+    .{ 9, 5, 6, 8, 7 },
+    .{ 9, 5, 7, 6, 8 },
+    .{ 9, 5, 7, 8, 6 },
+    .{ 9, 5, 8, 6, 7 },
+    .{ 9, 5, 8, 7, 6 },
+    .{ 9, 6, 5, 7, 8 },
+    .{ 9, 6, 5, 8, 7 },
+    .{ 9, 6, 7, 5, 8 },
+    .{ 9, 6, 7, 8, 5 },
+    .{ 9, 6, 8, 5, 7 },
+    .{ 9, 6, 8, 7, 5 },
+    .{ 9, 7, 5, 6, 8 },
+    .{ 9, 7, 5, 8, 6 },
+    .{ 9, 7, 6, 5, 8 },
+    .{ 9, 7, 6, 8, 5 },
+    .{ 9, 7, 8, 5, 6 },
+    .{ 9, 7, 8, 6, 5 },
+    .{ 9, 8, 5, 6, 7 },
+    .{ 9, 8, 5, 7, 6 },
+    .{ 9, 8, 6, 5, 7 },
+    .{ 9, 8, 6, 7, 5 },
+    .{ 9, 8, 7, 5, 6 },
+    .{ 9, 8, 7, 6, 5 },
+};
+
+fn doIt(m: *intcode.Machine) void {
+    if (m.run()) {} else |err| {
+        std.debug.warn("Machine {} failed to run successfully: {}\n", m.idx, err);
+    }
+}
+
+fn run(program: []i32, machines: *[5]intcode.Machine, permutations: [120][5]i32) !i32 {
+    var max: i32 = 0;
+
+    for (permutations) |inputs| {
+        // Reset program state each time
+        for (machines) |*machine, i| {
+            std.mem.copy(i32, machine.memory, program);
+            machine.ip = 0;
+            machine.idx = i;
+        }
+
+        // Phase inputs
+        for (inputs) |input, i| {
+            try machines[i].writeToInput(input);
+        }
+
+        // Provide starting value of 0
+        try machines[0].writeToInput(0);
+
+        // run the machines asychronously
+        var f0 = try std.Thread.spawn(&machines[0], doIt);
+        var f1 = try std.Thread.spawn(&machines[1], doIt);
+        var f2 = try std.Thread.spawn(&machines[2], doIt);
+        var f3 = try std.Thread.spawn(&machines[3], doIt);
+        var f4 = try std.Thread.spawn(&machines[4], doIt);
+
+        f0.wait();
+        f1.wait();
+        f2.wait();
+        f3.wait();
+        f4.wait();
+
+        const final = try machines[4].readFromOutput();
+        if (final > max)
+            max = final;
+    }
+
+    return max;
+}
+
 pub fn main() anyerror!void {
     var arena = std.heap.ArenaAllocator.init(std.heap.page_allocator);
     defer arena.deinit();
@@ -145,12 +314,9 @@ pub fn main() anyerror!void {
     // Now wire up the machines correctly. The output of each machine should be
     // the input to the next.
     const pipes: [6]intcode.CharDev = .{
-        try std.os.pipe(),
+        try std.os.pipe(), try std.os.pipe(),
-        try std.os.pipe(),
+        try std.os.pipe(), try std.os.pipe(),
-        try std.os.pipe(),
+        try std.os.pipe(), try std.os.pipe(),
-        try std.os.pipe(),
-        try std.os.pipe(),
-        try std.os.pipe(),
     };
 
     machines[0].input = pipes[0];
@@ -168,42 +334,11 @@ pub fn main() anyerror!void {
     machines[4].input = machines[3].output;
     machines[4].output = pipes[5];
 
-    // 120 phase permutations. Find the highest.
+    std.debug.warn("Day 7, Part 1: {}\n", try run(program, &machines, perm1));
-    var max: i32 = 0;
-    for (perm1) |inputs| {
-        for (machines) |*machine| {
-            std.mem.copy(i32, machine.memory, program);
-            machine.ip = 0;
-        }
-
-        // Phase inputs
-        for (inputs) |input, i| {
-            try machines[i].writeToInput(input);
-        }
-
-        // Provide starting value of 0
-        try machines[0].writeToInput(0);
-
-        // run the program
-        for (machines) |*machine, i| {
-            try machine.run();
-        }
-
-        const final = try machines[4].readFromOutput();
-        if (final > max)
-            max = final;
-
-        // Don't forget to free everything!
-        for (machines) |*machine, i| {
-            alloc.free(machine.memory);
-        }
-    }
-
-    std.debug.warn("Day 7, Part 1: {}\n", max);
 
     // In part 2, the machines need to be wired into a feedback loop.
     // To do this, drop pipe 6 and replace it with pipe 0
-    std.os.close(pipes[5][0]);
+    machines[0].input = machines[4].output;
-    std.os.close(pipes[5][1]);
+
-    machines[4].output = machines[0].input;
+    std.debug.warn("Day 7, Part 2: {}\n", try run(program, &machines, perm2));
 }

lib/intcode/intcode.zig

@@ -12,9 +12,6 @@ pub fn loadFromStream(alloc: *std.mem.Allocator, stream: *std.fs.File.InStream.S
     while (try stream.readUntilDelimiterOrEof(&buf, ',')) |num| {
         var trimmed = std.mem.trimRight(u8, num, "\r\n");
         program[i] = try std.fmt.parseInt(i32, trimmed, 10);
-
-        //        std.debug.warn("{},", program[i]);
-
         i += 1;
     }
 
@@ -92,6 +89,7 @@ const Instruction = struct {
 
 pub const Machine = struct {
     alloc: *std.mem.Allocator,
+    idx: usize = 0, // handy for debugging
 
     memory: []i32,
 
@@ -144,20 +142,22 @@ pub const Machine = struct {
         return self.__out(self.output, val);
     }
 
-    inline fn __in(self: *Machine, dev: CharDev) !i32 {
+    fn __in(self: *Machine, dev: CharDev) !i32 {
         const fd = dev[0]; // Read from the pipe
         var store: [4]u8 = undefined;
 
+        // std.debug.warn("{}: __in({} <- {})\n", self.idx, dev[0], dev[1]);
         var n = try std.os.read(fd, &store);
         std.debug.assert(n == 4); // TODO: handle partial reads
 
         return std.mem.readIntNative(i32, &store);
     }
 
-    inline fn __out(self: *Machine, dev: CharDev, val: i32) !void {
+    fn __out(self: *Machine, dev: CharDev, val: i32) !void {
         const fd = dev[1]; // Write to the pipe
         const bytes = std.mem.asBytes(&val);
 
+        // std.debug.warn("{}: __out({} -> {}, {})\n", self.idx, dev[1], dev[0], val);
         try std.os.write(fd, bytes);
     }
 
@@ -236,7 +236,9 @@ pub const Machine = struct {
                 }
             },
 
-            .END => {},
+            .END => {
+                //                std.debug.warn("{}: ended\n", self.idx);
+            },
         };
 
         // Only modify IP if the instruction itself has not