src/day11.zig

@@ -1,155 +0,0 @@
-const std = @import("std");
-const util = @import("util.zig");
-const mem = std.mem;
-
-pub fn main() !void {
-    const input = @embedFile("data/day11.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 Point(comptime T: type) type {
-    return struct { x: T, y: T };
-}
-
-fn findGaps(comptime T: type, alloc: mem.Allocator, occupied: std.AutoHashMap(T, void)) ![]T {
-    var it = occupied.keyIterator();
-    var sorted_occupied = try std.ArrayList(T).initCapacity(alloc, occupied.count());
-    defer sorted_occupied.deinit();
-    while (it.next()) |item| {
-        try sorted_occupied.append(item.*);
-    }
-    mem.sort(T, sorted_occupied.items, {}, std.sort.asc(T));
-
-    var gaps = std.ArrayList(T).init(alloc);
-    errdefer gaps.deinit();
-
-    var gap: T = 0;
-    var i: usize = 0;
-    const max_occ = if (sorted_occupied.items.len != 0) std.mem.max(T, sorted_occupied.items) else 0;
-    while (gap < max_occ and i < sorted_occupied.items.len) : (gap += 1) {
-        if (sorted_occupied.items[i] != gap) {
-            try gaps.append(gap);
-        } else {
-            i += 1;
-        }
-    }
-
-    return gaps.toOwnedSlice();
-}
-
-fn expand(comptime T: type, alloc: mem.Allocator, galaxies: []Point(T), scale: T) !void {
-    var seen_cols = std.AutoHashMap(T, void).init(alloc);
-    defer seen_cols.deinit();
-    var seen_rows = std.AutoHashMap(T, void).init(alloc);
-    defer seen_rows.deinit();
-
-    for (galaxies) |galaxy| {
-        try seen_cols.put(galaxy.x, {});
-        try seen_rows.put(galaxy.y, {});
-    }
-
-    var gap_cols = try findGaps(T, alloc, seen_cols);
-    defer alloc.free(gap_cols);
-    var gap_rows = try findGaps(T, alloc, seen_rows);
-    defer alloc.free(gap_rows);
-
-    for (0..galaxies.len) |i| {
-        const galaxy = galaxies[i];
-
-        var col_offset: T = 0;
-        for (gap_cols) |gap| {
-            if (gap > galaxy.x) break;
-            col_offset += scale - 1;
-        }
-
-        var row_offset: T = 0;
-        for (gap_rows) |gap| {
-            if (gap > galaxy.y) break;
-            row_offset += scale - 1;
-        }
-
-        galaxies[i] = Point(T){ .x = galaxy.x + col_offset, .y = galaxy.y + row_offset };
-    }
-}
-
-fn absDiff(comptime T: type, a: T, b: T) T {
-    return @max(a, b) - @min(a, b);
-}
-
-fn solvePart(alloc: mem.Allocator, input: []const u8, scale: usize) !usize {
-    var galaxies = std.ArrayList(Point(usize)).init(alloc);
-    defer galaxies.deinit();
-
-    var it = util.splitLines(input);
-    var y: usize = 0;
-    while (it.next()) |line| {
-        if (line.len == 0) continue;
-        var x: usize = 0;
-        for (line) |char| {
-            switch (char) {
-                '.' => {},
-                '#' => try galaxies.append(Point(usize){ .x = x, .y = y }),
-                else => unreachable,
-            }
-            x += 1;
-        }
-        y += 1;
-    }
-
-    try expand(usize, alloc, galaxies.items, scale);
-
-    var distance: usize = 0;
-    for (galaxies.items, 0..) |a, i| {
-        for (galaxies.items[i + 1 .. galaxies.items.len]) |b| {
-            const d = absDiff(usize, a.x, b.x) + absDiff(usize, a.y, b.y);
-            distance += d;
-        }
-    }
-
-    return distance;
-}
-
-fn solve(alloc: mem.Allocator, input: []const u8) !Solution {
-    return .{ .a = try solvePart(alloc, input, 2), .b = try solvePart(alloc, input, 1_000_000) };
-}
-
-test "silver" {
-    const input =
-        \\...#......
-        \\.......#..
-        \\#.........
-        \\..........
-        \\......#...
-        \\.#........
-        \\.........#
-        \\..........
-        \\.......#..
-        \\#...#.....
-    ;
-    const sln = try solvePart(std.testing.allocator, input, 2);
-    try std.testing.expectEqual(@as(usize, 374), sln);
-}
-
-test "gold" {
-    const input =
-        \\...#......
-        \\.......#..
-        \\#.........
-        \\..........
-        \\......#...
-        \\.#........
-        \\.........#
-        \\..........
-        \\.......#..
-        \\#...#.....
-    ;
-    try std.testing.expectEqual(@as(usize, 1030), try solvePart(std.testing.allocator, input, 10));
-    try std.testing.expectEqual(@as(usize, 8410), try solvePart(std.testing.allocator, input, 100));
-}