wip part2

src/day14.zig

@@ -0,0 +1,94 @@
+const std = @import("std");
+const util = @import("util.zig");
+const mem = std.mem;
+
+pub fn main() !void {
+    const input = @embedFile("data/day14.txt");
+    const sln = try solve(util.gpa, input);
+    std.debug.print("{d}\n", .{sln.a});
+    std.debug.print("{d}\n", .{sln.b});
+}
+
+const Solution = struct {
+    a: usize,
+    b: usize,
+};
+
+fn northWeight(alloc: mem.Allocator, grid: [][]u8) !usize {
+    var next_slot = try alloc.alloc(u32, grid[0].len);
+    defer alloc.free(next_slot);
+    @memset(next_slot, 0);
+
+    var weight: usize = 0;
+    for (grid, 0..) |line, row| {
+        for (line, 0..) |char, col| {
+            switch (char) {
+                'O' => {
+                    weight += grid.len - next_slot[col];
+                    next_slot[col] += 1;
+                },
+                '#' => next_slot[col] = @as(u32, @intCast(row)) + 1,
+                else => {},
+            }
+        }
+    }
+    return weight;
+}
+
+fn spin(grid: [][]u8, n: usize) void {
+    _ = grid;
+    for (0..n) |_| {}
+}
+
+fn solve(alloc: mem.Allocator, input: []const u8) !Solution {
+    var height = mem.count(u8, input, &[_]u8{'\n'});
+    if (input[input.len - 1] != '\n') height += 1;
+
+    var grid = try alloc.alloc([]u8, height);
+    defer alloc.free(grid);
+
+    var it = util.splitLines(input);
+    var row: u32 = 0;
+    while (it.next()) |line| {
+        if (line.len == 0) continue;
+        grid[row] = try alloc.alloc(u8, line.len);
+        @memcpy(grid[row], line);
+        row += 1;
+    }
+
+    const w = try northWeight(alloc, grid);
+    spin(grid, 1000000000);
+    const v = try northWeight(alloc, grid);
+    _ = v;
+
+    for (grid) |line| {
+        alloc.free(line);
+    }
+    return .{ .a = w, .b = 0 };
+}
+
+test "silver" {
+    const input =
+        \\O....#....
+        \\O.OO#....#
+        \\.....##...
+        \\OO.#O....O
+        \\.O.....O#.
+        \\O.#..O.#.#
+        \\..O..#O..O
+        \\.......O..
+        \\#....###..
+        \\#OO..#....
+    ;
+    const sln = try solve(std.testing.allocator, input);
+    try std.testing.expectEqual(@as(usize, 136), sln.a);
+}
+
+test "gold" {
+    const input =
+        \\
+    ;
+    _ = input;
+    // const sln = try solve(std.testing.allocator, input);
+    // try std.testing.expectEqual(@as(usize, 0), sln.b);
+}