Day 2.1, horrible but working

03/src/main.zig

@@ -1,18 +1,14 @@
 const std = @import("std");
 
-const max = 512;
-const xOrigin = max / 2;
-const yOrigin = max / 2;
-
 const Error = error{ParseError};
 
-const State = enum(u8) {
-    Empty,
-    Origin,
-    Line,
-    Intersect,
+const Point = struct {
+    X: i32,
+    Y: i32,
 };
 
+const Points = std.ArrayList(Point);
+
 const Direction = enum(u8) {
     Up = 'U',
     Right = 'R',
@@ -30,11 +26,9 @@ const Direction = enum(u8) {
     }
 };
 
-const Grid = [max][max]State;
-
 const Step = struct {
     d: Direction,
-    l: u32,
+    l: i32,
 
     pub fn parse(in: []const u8) anyerror!Step {
         if (in.len < 2) {
@@ -43,86 +37,55 @@ const Step = struct {
 
         return Step{
             .d = try Direction.parse(in[0]),
-            .l = try std.fmt.parseInt(u32, in[1..in.len], 10),
+            .l = try std.fmt.parseInt(i32, in[1..in.len], 10),
         };
     }
 };
 
 const World = struct {
-    x: u32,
-    y: u32,
-    grid: *Grid,
+    entries: Points,
+    pos: Point,
 
-    pub fn init(self: *World) void {
-        for (self.grid) |y, y_offset| {
-            for (y) |x, x_offset| {
-                self.grid[y_offset][x_offset] = State.Empty;
-            }
-        }
-    }
-
-    pub fn display(self: *World) void {
-        for (self.grid) |y, y_offset| {
-            for (y) |x, x_offset| {
-                var chr = switch (x) {
-                    State.Empty => " ",
-                    State.Line => ".",
-                    State.Origin => "o",
-                    State.Intersect => "*",
-                };
-
-                std.debug.warn("{}", chr);
-            }
-            std.debug.warn("\n");
-        }
-    }
-
-    pub fn step(self: *World, in: Step, compare: *Grid) void {
+    pub fn step(self: *World, in: Step) anyerror!void {
         std.debug.warn("Step: {}\n", in);
 
         switch (in.d) {
             .Up => {
-                self.lineY(self.y - in.l, self.y - 1, compare);
-                self.y -= in.l;
+                try self.lineY(self.pos.Y - in.l, self.pos.Y - 1);
+                self.pos.Y -= in.l;
             },
             .Down => {
-                self.lineY(self.y + 1, self.y + in.l, compare);
-                self.y += in.l;
+                try self.lineY(self.pos.Y + 1, self.pos.Y + in.l);
+                self.pos.Y += in.l;
             },
             .Left => {
-                self.lineX(self.x - in.l, self.x - 1, compare);
-                self.x -= in.l;
+                try self.lineX(self.pos.X - in.l, self.pos.X - 1);
+                self.pos.X -= in.l;
             },
             .Right => {
-                self.lineX(self.x + 1, self.x + in.l, compare);
-                self.x += in.l;
+                try self.lineX(self.pos.X + 1, self.pos.X + in.l);
+                self.pos.X += in.l;
             },
         }
     }
 
-    fn lineX(self: *World, start: u32, end: u32, compare: *Grid) void {
-        var x: u32 = start;
+    fn lineX(self: *World, start: i32, end: i32) anyerror!void {
+        var x: i32 = start;
         while (x <= end) : (x += 1) {
-            self.fill(x, self.y, compare);
+            try self.fill(x, self.pos.Y);
         }
     }
 
-    fn lineY(self: *World, start: u32, end: u32, compare: *Grid) void {
-        var y: u32 = start;
+    fn lineY(self: *World, start: i32, end: i32) anyerror!void {
+        var y: i32 = start;
         while (y <= end) : (y += 1) {
-            self.fill(self.x, y, compare);
+            try self.fill(self.pos.X, y);
         }
     }
 
-    fn fill(self: *World, x: u32, y: u32, compare: *Grid) void {
-        std.debug.warn("\tFilling {},{}\n", x, y);
-
-        var newVal: State = switch (compare[y][x]) {
-            .Line => .Intersect,
-            else => .Line,
-        };
-
-        self.grid[y][x] = newVal;
+    fn fill(self: *World, x: i32, y: i32) anyerror!void {
+        //self.entries = try self.alloc.realloc(self.entries, self.entries.len+1);
+        self.entries.appendAssumeCapacity(Point{ .X = x, .Y = y });
     }
 };
 
@@ -145,9 +108,11 @@ fn getLine(stream: *std.fs.File.InStream.Stream) anyerror![]Step {
 }
 
 fn manhattan(x: i32, y: i32) u32 {
-    return std.math.absCast(x - xOrigin) + std.math.absCast(y - yOrigin);
+    return std.math.absCast(x) + std.math.absCast(y);
 }
 
+const maxEntries = 1024 * 1024;
+
 pub fn main() anyerror!void {
     var arena = std.heap.ArenaAllocator.init(std.heap.page_allocator);
     defer arena.deinit();
@@ -156,58 +121,35 @@ pub fn main() anyerror!void {
     const file = std.io.getStdIn();
     const stream = &file.inStream().stream;
 
-    var grid = try alloc.create(Grid);
-
     var world: World = World{
-        .x = xOrigin,
-        .y = yOrigin,
-        .grid = grid,
+        .entries = try Points.initCapacity(alloc, maxEntries),
+        .pos = Point{ .X = 0, .Y = 0 },
     };
 
-    world.init();
-    var compare = std.mem.dupe(alloc, Grid, grid);
-
     // Line 1
     for (try getLine(stream)) |item| {
-        world.step(item, compare);
+        try world.step(item);
     }
 
     // reset to origin
-    //std.mem.copy(compare, world.grid);
-    world.x = xOrigin;
-    world.y = yOrigin;
+    const entriesA = world.entries;
+    world.entries = try Points.initCapacity(alloc, maxEntries);
+    world.pos = Point{ .X = 0, .Y = 0 };
 
     // Line 2
     for (try getLine(stream)) |item| {
-        world.step(item, compare);
+        try world.step(item);
     }
 
-    // Ignore the origin
-    world.grid[yOrigin][xOrigin] = State.Origin;
+    const entriesB = world.entries;
 
-    // detect collisions
-    var minMH: u32 = undefined;
-    var found: bool = false;
-    for (world.grid) |y, yOff| {
-        for (y) |x, xOff| {
-            if (x == State.Intersect) {
-                const mh = manhattan(@intCast(i32, xOff), @intCast(i32, yOff));
-                std.debug.warn("Intersect! {},{} : {}\n", xOff, yOff, mh);
-                if (found) {
-                    if (minMH > mh) {
-                        minMH = mh;
-                    }
-                } else {
-                    found = true;
-                    minMH = mh;
-                }
+    std.debug.warn("A: {} entries\nB: {} entries\n", entriesA.len, entriesB.len);
+
+    for (entriesA.toSlice()) |a| {
+        for (entriesB.toSlice()) |b| {
+            if (a.X == b.X and a.Y == b.Y) {
+                std.debug.warn("Match! {} => {}\n", a, manhattan(a.X, a.Y));
             }
         }
     }
-
-    if (found) {
-        std.debug.warn("Smallest manhattan: {}\n", minMH);
-    }
-
-    //    world.display();
 }