WIP: implement part 2

This requires terabytes of RAM. Or a couple million dollars in today's
economy.

src/days/day10.zig

@@ -3,12 +3,12 @@ const std = @import("std");
 pub const title = "Day 10: Factory";
 
 pub fn run(allocator: std.mem.Allocator) !void {
-    const input = @embedFile("./input/day10.txt");
-    //const input =
-    //    \\[.##.] (3) (1,3) (2) (2,3) (0,2) (0,1) {3,5,4,7}
-    //    \\[...#.] (0,2,3,4) (2,3) (0,4) (0,1,2) (1,2,3,4) {7,5,12,7,2}
-    //    \\[.###.#] (0,1,2,3,4) (0,3,4) (0,1,2,4,5) (1,2) {10,11,11,5,10,5}
-    //    ;
+    //const input = @embedFile("./input/day10.txt");
+    const input =
+        \\[.##.] (3) (1,3) (2) (2,3) (0,2) (0,1) {3,5,4,7}
+        \\[...#.] (0,2,3,4) (2,3) (0,4) (0,1,2) (1,2,3,4) {7,5,12,7,2}
+        \\[.###.#] (0,1,2,3,4) (0,3,4) (0,1,2,4,5) (1,2) {10,11,11,5,10,5}
+        ;
     //const input =
     //    \\[#...#] (1,3) (2,3,4) (0,2,3) (0,1,2) (2,3) {37,24,60,50,16}
     //    \\[##...#..] (0,1,3,5,6) (0,1,5) (4) (5,6) (0,4,7) (1,2,5) (3) {23,18,2,26,14,36,25,7}
@@ -18,11 +18,11 @@ pub fn run(allocator: std.mem.Allocator) !void {
 
     var accumulator: usize = 0;
 
-    var light_states: std.ArrayList(std.bit_set.IntegerBitSet(Machine.MaxLightCount)) = .empty;
-    defer light_states.deinit(allocator);
+    var jolt_states: std.ArrayList([Machine.MaxLightCount]u9) = .empty;
+    defer jolt_states.deinit(allocator);
 
-    var next_light_states: std.ArrayList(std.bit_set.IntegerBitSet(Machine.MaxLightCount)) = .empty;
-    defer next_light_states.deinit(allocator);
+    var next_jolt_states: std.ArrayList([Machine.MaxLightCount]u9) = .empty;
+    defer next_jolt_states.deinit(allocator);
 
     var i: usize = 0;
     while (lines.next()) |line| {
@@ -33,27 +33,32 @@ pub fn run(allocator: std.mem.Allocator) !void {
 
         std.debug.print("{f}\n", .{machine});
 
-        light_states.clearRetainingCapacity();
-        try light_states.append(allocator, .initEmpty());
+        jolt_states.clearRetainingCapacity();
+        try jolt_states.append(allocator, [_]u9{0} ** Machine.MaxLightCount);
 
         var buttons_pressed: usize = 0;
 
         outer: while (true) {
-            next_light_states.clearRetainingCapacity();
+            next_jolt_states.clearRetainingCapacity();
 
             buttons_pressed += 1;
-            for (light_states.items) |state| {
+            for (jolt_states.items) |state| {
                 for (machine.buttons) |button| {
-                    const next_state = state.xorWith(button);
-                    if (next_state.eql(machine.lights_goal)) {
+                    var next_state: [Machine.MaxLightCount]u9 = state;
+                    for (0..Machine.MaxLightCount) |index| {
+                        if (button.isSet(index)) {
+                            next_state[index] += 1;
+                        }
+                    }
+                    if (std.mem.eql(u9, &next_state, machine.jolts_goal)) {
                         break :outer;
                     }
-                    try next_light_states.append(allocator, next_state);
+                    try next_jolt_states.append(allocator, next_state);
                 }
             }
 
-            light_states.clearRetainingCapacity();
-            try light_states.appendSlice(allocator, next_light_states.items);
+            jolt_states.clearRetainingCapacity();
+            try jolt_states.appendSlice(allocator, next_jolt_states.items);
         }
 
         std.debug.print("machine {d} requires {d} button presses\n", .{i, buttons_pressed});
@@ -73,6 +78,7 @@ pub fn run(allocator: std.mem.Allocator) !void {
 const Machine = struct {
     lights_goal: std.bit_set.IntegerBitSet(MaxLightCount),
     buttons: []std.bit_set.IntegerBitSet(MaxLightCount),
+    jolts_goal: []u9,
 
     allocator: std.mem.Allocator,
 
@@ -86,6 +92,8 @@ const Machine = struct {
         var lights_goal: std.bit_set.IntegerBitSet(MaxLightCount) = .initEmpty();
         var buttons: std.ArrayList(std.bit_set.IntegerBitSet(MaxLightCount)) = .empty;
         defer buttons.deinit(allocator);
+        var jolts_goal: std.ArrayList(u9) = .empty;
+        defer jolts_goal.deinit(allocator);
 
         var line_iter = std.mem.tokenizeScalar(u8, line, ' ');
         while (line_iter.next()) |part| {
@@ -103,29 +111,51 @@ const Machine = struct {
                 }
 
                 try buttons.append(allocator, button);
+            } else if (part[0] == '{' and part[part.len - 1] == '}') {
+                var values_iter = std.mem.tokenizeScalar(u8, p, ',');
+                while (values_iter.next()) |value| {
+                    try jolts_goal.append(allocator, try std.fmt.parseUnsigned(u9, value, 10));
+                }
             }
         }
 
         const buttons_slice = try buttons.toOwnedSlice(allocator);
         errdefer allocator.free(buttons_slice);
 
+        const jolts_goal_slice = try jolts_goal.toOwnedSlice(allocator);
+        errdefer allocator.free(jolts_goal_slice);
+
         return .{
             .lights_goal = lights_goal,
             .buttons = buttons_slice,
+            .jolts_goal = jolts_goal_slice,
             .allocator = allocator,
         };
     }
 
     pub fn deinit(self: Self) void {
         self.allocator.free(self.buttons);
+        self.allocator.free(self.jolts_goal);
     }
 
     pub fn format(self: Self, w: *std.Io.Writer) std.Io.Writer.Error!void {
         try w.print("[{b}]", .{self.lights_goal.mask});
         try w.writeByte(' ');
-        for (self.buttons) |button| {
+        for (self.buttons, 0..) |button, i| {
             try w.print("({b})", .{button.mask});
+            if (i < self.buttons.len - 1) {
+                try w.writeByte(' ');
             }
         }
+        try w.writeByte(' ');
+        try w.writeByte('{');
+        for (self.jolts_goal, 0..) |jolt, i| {
+            try w.print("{d}", .{jolt});
+            if (i < self.jolts_goal.len - 1) {
+                try w.writeByte(',');
+            }
+        }
+        try w.writeByte('}');
+    }
 };