day x

day5/day5_part1.zig

@@ -0,0 +1,133 @@
+const std = @import("std");
+const in = @embedFile("in");
+
+fn array_includes(comptime T: type, haystack: []T, needle: T) bool {
+    for (haystack) |item| {
+        if (item == needle) {
+            return true;
+        }
+    }
+    return false;
+}
+
+pub fn main() !void {
+    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
+    const ally = gpa.allocator();
+    defer _ = gpa.deinit();
+
+    var lines = std.ArrayList(std.ArrayList(u32)).init(ally);
+    var incorrect_line_idxs = std.ArrayList(u32).init(ally);
+    defer {
+        for (lines.items) |*line| {
+            line.deinit();
+        }
+        lines.deinit();
+        incorrect_line_idxs.deinit();
+    }
+
+    var dependencies = std.AutoHashMap(u32, std.ArrayList(u32)).init(ally);
+    defer {
+        var iter = dependencies.iterator();
+        while (iter.next()) |entry| {
+            entry.value_ptr.deinit();
+        }
+        dependencies.deinit();
+    }
+
+    var in_lines = std.mem.tokenize(u8, in, "\n");
+    var parsing_dependencies = false;
+    var i: u32 = 0;
+    while (in_lines.next()) |line| {
+        if (std.mem.indexOf(u8, line, "|")) |_| {
+            parsing_dependencies = true;
+        } else {
+            parsing_dependencies = false;
+        }
+
+        if (line.len > 0 and parsing_dependencies) {
+            var dependance = std.mem.split(u8, line, "|");
+            const num1 = try std.fmt.parseInt(u32, dependance.next().?, 10);
+            const num2 = try std.fmt.parseInt(u32, dependance.next().?, 10);
+
+            var entry = try dependencies.getOrPut(num2);
+            if (!entry.found_existing) {
+                entry.value_ptr.* = std.ArrayList(u32).init(ally);
+            }
+
+            try entry.value_ptr.append(num1);
+        } else if (line.len > 0 and !parsing_dependencies) {
+            var ints = std.mem.split(u8, line, ",");
+            var intLine = std.ArrayList(u32).init(ally);
+            while (ints.next()) |int| {
+                try intLine.append(try std.fmt.parseInt(u32, int, 10));
+            }
+            try lines.append(intLine);
+        }
+        i += 1;
+    }
+
+    // Part 1
+    var middle_page_number_sum: u32 = 0;
+    for (lines.items, 0..) |line, lidx| {
+        var is_correct = true;
+        outer: for (line.items, 0..) |num1, j| {
+            for (line.items[0..j]) |num2| {
+                const deps = dependencies.get(num1);
+
+                if (deps == null) {
+                    is_correct = false;
+                    break :outer;
+                }
+
+                var found = false;
+                for (deps.?.items) |dep| {
+                    if (dep == num2) {
+                        found = true;
+                        break;
+                    }
+                }
+                if (!found) {
+                    is_correct = false;
+                    break :outer;
+                }
+            }
+        }
+
+        if (is_correct) {
+            middle_page_number_sum += line.items[line.items.len / 2];
+        } else {
+            try incorrect_line_idxs.append(@intCast(lidx));
+        }
+    }
+    std.debug.print("Part1: {}\n", .{middle_page_number_sum});
+
+    // Part 2
+    middle_page_number_sum = 0;
+    for (incorrect_line_idxs.items) |idx| {
+        const line = lines.items[idx];
+        var fixed_line = std.ArrayList(u32).init(ally);
+        defer fixed_line.deinit();
+
+        for (line.items) |num| {
+            const deps = dependencies.get(num);
+
+            if (deps == null) {
+                try fixed_line.insert(0, num);
+                continue;
+            }
+
+            var j: usize = 0;
+            for (fixed_line.items) |comparison_num| {
+                if (array_includes(u32, deps.?.items, comparison_num)) {
+                    j += 1;
+                    continue;
+                }
+            }
+            try fixed_line.insert(j, num);
+        }
+
+        middle_page_number_sum += fixed_line.items[fixed_line.items.len / 2];
+    }
+
+    std.debug.print("Part 2: {}\n", .{middle_page_number_sum});
+}

day5/test

@@ -0,0 +1,28 @@
+47|53
+97|13
+97|61
+97|47
+75|29
+61|13
+75|53
+29|13
+97|29
+53|29
+61|53
+97|53
+61|29
+47|13
+75|47
+97|75
+47|61
+75|61
+47|29
+75|13
+53|13
+
+75,47,61,53,29
+97,61,53,29,13
+75,29,13
+75,97,47,61,53
+61,13,29
+97,13,75,29,47

day6/day6_part1.zig

@@ -0,0 +1,134 @@
+const std = @import("std");
+const in = @embedFile("in");
+
+const Direction = struct {
+    x: i32,
+    y: i32,
+
+    const Left = Direction{ .x = -1, .y = 0 };
+    const Right = Direction{ .x = 1, .y = 0 };
+    const Up = Direction{ .x = 0, .y = -1 };
+    const Down = Direction{ .x = 0, .y = 1 };
+
+    pub fn eql(self: Direction, other: Direction) bool {
+        return self.x == other.x and self.y == other.y;
+    }
+};
+
+fn array_includes(comptime T: type, haystack: []T, needle: T) bool {
+    for (haystack) |item| {
+        if (item == needle) {
+            return true;
+        }
+    }
+    return false;
+}
+
+fn turn_right(direction: Direction) Direction {
+    if (direction.eql(Direction.Up)) {
+        return Direction.Right;
+    } else if (direction.eql(Direction.Right)) {
+        return Direction.Down;
+    } else if (direction.eql(Direction.Down)) {
+        return Direction.Left;
+    } else if (direction.eql(Direction.Left)) {
+        return Direction.Up;
+    }
+    unreachable;
+}
+
+fn find_guard(lines: std.ArrayList(std.ArrayList(i8))) [2]i32 {
+    for (lines.items, 0..) |line, y| {
+        for (line.items, 0..) |item, x| {
+            if (item == 1) {
+                return .{ @intCast(x), @intCast(y) };
+            }
+        }
+    }
+    unreachable;
+}
+
+fn print_lines(lines: std.ArrayList(std.ArrayList(i8))) void {
+    for (lines.items) |line| {
+        for (line.items) |item| {
+            switch (item) {
+                -1 => std.debug.print("#", .{}),
+                0 => std.debug.print(".", .{}),
+                1 => std.debug.print("^", .{}),
+                2 => std.debug.print("V", .{}),
+                else => std.debug.print(" ", .{}),
+            }
+        }
+        std.debug.print("\n", .{});
+    }
+}
+
+fn count_visited(lines: std.ArrayList(std.ArrayList(i8))) u32 {
+    var count: u32 = 0;
+    for (lines.items) |line| {
+        for (line.items) |e| {
+            if (e == 2 or e == 1) count += 1;
+        }
+    }
+    return count;
+}
+
+fn move(lines: std.ArrayList(std.ArrayList(i8)), direction: Direction) void {
+    // print_lines(lines);
+    // std.debug.print("\n", .{});
+
+    const pos = find_guard(lines);
+    var x = pos[0];
+    var y = pos[1];
+    lines.items[@intCast(y)].items[@intCast(x)] = 2; // 2 for already visited
+    x += direction.x;
+    y += direction.y;
+
+    if (y < 0 or y >= lines.items.len or x < 0 or x >= lines.items[@intCast(y)].items.len) {
+        return;
+    }
+
+    if (lines.items[@intCast(y)].items[@intCast(x)] == -1) {
+        x -= direction.x;
+        y -= direction.y;
+        lines.items[@intCast(y)].items[@intCast(x)] = 1;
+        return move(lines, turn_right(direction));
+    }
+
+    lines.items[@intCast(y)].items[@intCast(x)] = 1;
+    return move(lines, direction);
+}
+
+pub fn main() !void {
+    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
+    const ally = gpa.allocator();
+    defer _ = gpa.deinit();
+
+    var lines = std.ArrayList(std.ArrayList(i8)).init(ally);
+    defer {
+        for (lines.items) |*line| {
+            line.deinit();
+        }
+        lines.deinit();
+    }
+
+    var in_lines = std.mem.tokenize(u8, in, "\n");
+    while (in_lines.next()) |linestr| {
+        var line = std.ArrayList(i8).init(ally);
+        for (linestr) |c| {
+            const value: i8 = switch (c) {
+                '#' => -1,
+                '.' => 0,
+                '^' => 1,
+                else => -2,
+            };
+            try line.append(value);
+        }
+        try lines.append(line);
+    }
+
+    move(lines, Direction.Up);
+    const moves = count_visited(lines);
+
+    std.debug.print("{d}\n", .{moves});
+}

day6/in

@@ -0,0 +1,130 @@
+..#....##....................#...#...#..........................................................................................#.
+.....#..............................................#....#.....#.....#..............................#.......#...#.............#...
+............#.#.........................................#...................#..#...........................###..........#.....#...
+.....#.....#.............#...........................................................#.#.................#.........#..............
+.......................#...........................#................#...........#......#.....................#...#.......#....#...
+...#........................................#....................#.......#........##.##.........#.........................#.......
+......#...........#....................#...........#.............................#........................#....................#..
+...........................#...................................#...............#.........................................#........
+........#...........#................................................................#............#...............................
+.........................#......#.......#..............#......#.................#..................#...................#..........
+............#......................................................#..............................#........#....#.................
+........#.....................................................................#..............#....................................
+..#............................#.................#.#............#.................................................................
+...#................#.....................#.................................................#...................#.................
+......#...................#........................................................................................#..#...........
+.....................##..#........................................#...................#............#.....#........................
+.......#.................#..........#...........................#.......#..............#..........................................
+.............#........#........#..........#................#.........#.##.................................#.......#...........#...
+.#..............................................................#..#.....................................#.................##.....
+.........................#.#.......#.#..................................................#....................#.......#.........#..
+.............#................................................#..#................#.............#.....#...........................
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+...................#....................#..............#......................#..............#........#......................#....
+.............#..................................................................................#................#.....##.........
+.#.............................#........#................#..#..#.....#...........###..............................................
+.......................................................#.........................#.............................#..................
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+......#.......##.........#..................................................................#.#..#.........#.........#.......#....
+..#...........#..........#........#....#..........#..................#.............#.............#................................
+#................................##...........#......#....##......#..#.....................................#.........#..#.........
+...#...#.#.......................#......................................#.........#......#...............#........................
+..#...#.......................................................#..................#.........................................#......
+...#.....#.....#..........#....................#..................#.........................#...............#...#..#....#.........
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+...............#.....#........#..#................................................................................................
+#...........................#.#..............................#........^......#.................................#.....#............
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+...........#...#............................#....................#.......................................................#........
+.#.....................................................................................................#.....#....................
+.#.......#..............#.....................#.....................#............#........................#.......................
+............................#...#................................................#................................#...............
+..........#...............#..........................#................#.........................#.......#.#.......................
+..............................#.............................................................................................#.....
+..............................................#....#...............................................#.....#........................
+.........#...................................................#...............#.....#................#.............................
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+..........................#...........#.#...#.....................................#......................#...........#..#.........
+....#...............#..............#.............................#....#.....#....#................................................
+....#.#...........#..............#.................................................................#..............................
+.....#.......#..........................................................................................#.#.......................
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+.#....#..............................#..........#................#.............................................................#..
+....#.......................#........#.....#..............#...............#..#........................................#...........
+...........................................................................#......................................................
+...#.........#..#.......................................................#..#..............................#.......................
+.............#...................................................................#.......................#...#...........#........
+.....#........................#....................#...................#................................#.........................
+.........#......#...........................................#.......#....................#........................................
+...........................................................#...........................#.............................#............
+..........................#..............#........................................#......#.........#.#.............#........#.....
+.........#..............#..#...........................#......#.......................#..#..#.............#.......................
+...#.................#...............................................................................................#............
+................#.....#.#...........................#......................#....................................#...#.#...........
+..................#.....#...............................................................#............................#....#..#....
+...............................#................................................#.............#..........................#........
+..#...........#................................................#.........................................#...............##......#
+...............................#..................##..#...........................................#................#..............
+...........................#........#.........#....................................................#......#......#................
+..................................#................#..................#.....#..................#...................#.....#........
+.......#...#................................................................##...........................................#........
+..............#..#.......#............................#...................#....#...........................#..#......#............
+...............#............#................................................................................#..............#.....
+...............#.....#........................#.........#.........#...#................#....#.........#...........................
+................................#........................................................................#.........#..............
+.............#..................#...#................................#..............#................................#.........#..
+.....................#.#.............................#......#..................................#.........##....#.................#
+......#.........#...#.................................#..........#.#......................#.......#........#......................
+.....#....................#......................#.........#.....................#.........................................#......
+.........##.....................#....#.#....#....................................................................................#
+.................................................#.#....#....................#...............##..#................................
+..##.......#........#.......................#.....................................................................#...........#.##
+..#...........##........##......#..........#....................#.....#.....#..................#.....#............................
+..........................#.......................#.....#.........................................................................
+.#...........................#..............#...#...........#.....#.......#....#............#.....#..................#....#......#
+.................#.......................#....#...#..................#......#............................#.....................#..
+.....##..#........#........................#......#........................#....#......................##.........................
+...#....................................................................................................#.......................#.
+.......................#...#..............#..................#............#.#.........#....#...#..................................
+...........#.......................#.......................#.......#....#.....#..................#...................#............
+..................#......................................................................#.......#..........................#.....
+.......#..................#.............#..#........##........#..##........##.....##...#................#..#.......#..............
+........#................#..............................#..#......................................................................
+...................#....#.........................#...........#.#......##.........#.#..................#..#.#....#........#.......
+.............#......#.....................................................#.......................................................
+.........................#.......................#..................#.........................#...............................#..#
+..#...........................#............#.................##...#................#.................#................#...........
+.....#...............#.....#..........#..................................#.#........................#.....###.#...................
+...............................................#.............#......................................................#.............
+......#......................#..............#.................#.#........#.................#......................................
+........................#.......................................#....................#.......#.#..#...............................

day6/test

@@ -0,0 +1,10 @@
+....#.....
+.........#
+..........
+..#.......
+.......#..
+..........
+.#..^.....
+........#.
+#.........
+......#...