diff options
| -rw-r--r-- | day_08.zig | 124 | ||||
| -rw-r--r-- | inputs/day_08 | 100 | ||||
| -rw-r--r-- | main.zig | 1 |
3 files changed, 225 insertions, 0 deletions
diff --git a/day_08.zig b/day_08.zig new file mode 100644 index 0000000..4b5ae38 --- /dev/null +++ b/day_08.zig @@ -0,0 +1,124 @@ +const std = @import("std"); +const Result = @import("util/aoc.zig").Result; + +pub fn puzzle_1(input: []const u8) Result { + var grid = std.mem.zeroes([99][99]u8); + load_grid(&grid, input); + + var count: i32 = 0; + + for (grid) |_, y| { + for (grid[y]) |_, x| { + const position = [_]usize{ y, x }; + if (is_visible_left(position, grid) or + is_visible_right(position, grid) or is_visible_up(position, grid) or + is_visible_down(position, grid)) count += 1; + } + } + + return .{ .int = count }; +} + +pub fn puzzle_2(input: []const u8) Result { + var grid = std.mem.zeroes([99][99]u8); + load_grid(&grid, input); + + var max: u32 = 0; + + for (grid) |_, y| { + for (grid[y]) |_, x| { + const position = [_]usize{ y, x }; + const down = view_distance_down(position, grid); + const left = view_distance_left(position, grid); + const right = view_distance_right(position, grid); + const up = view_distance_up(position, grid); + + const n: u32 = down * up * left * right; + max = std.math.max(n, max); + } + } + + return .{ .int = @intCast(i32, max) }; +} + +fn load_grid(grid: *[99][99]u8, input: []const u8) void { + var iter = std.mem.split(u8, input, "\n"); + var row_idx: usize = 0; + while (iter.next()) |line| : (row_idx += 1) { + for (line) |char, column| { + grid[row_idx][column] = std.fmt.parseInt(u8, &[_]u8{char}, 0) catch unreachable; + } + } +} + +fn is_visible_down(pos: [2]usize, grid: [99][99]u8) bool { + var max = grid[pos[0]][pos[1]]; + var i = pos[0] + 1; + for (grid[i..]) |_| { + if (grid[i][pos[1]] >= max) return false; + i += 1; + } + return true; +} + +fn is_visible_up(pos: [2]usize, grid: [99][99]u8) bool { + var max = grid[pos[0]][pos[1]]; + for (grid[0..pos[0]]) |row| if (row[pos[1]] >= max) return false; + return true; +} + +fn is_visible_right(pos: [2]usize, grid: [99][99]u8) bool { + var max = grid[pos[0]][pos[1]]; + for (grid[pos[0]][pos[1] + 1 ..]) |n| if (n >= max) return false; + return true; +} + +fn is_visible_left(pos: [2]usize, grid: [99][99]u8) bool { + var max = grid[pos[0]][pos[1]]; + for (grid[pos[0]][0..pos[1]]) |n| if (n >= max) return false; + return true; +} + +fn view_distance_down(pos: [2]usize, grid: [99][99]u8) u32 { + var max = grid[pos[0]][pos[1]]; + var treecount: u8 = 0; + var i = pos[0] + 1; + for (grid[i..]) |_| { + if (grid[i][pos[1]] >= max) return treecount + 1; + treecount += 1; + i += 1; + } + return treecount; +} + +fn view_distance_right(pos: [2]usize, grid: [99][99]u8) u32 { + var max = grid[pos[0]][pos[1]]; + var treecount: u8 = 0; + for (grid[pos[0]][pos[1] + 1 ..]) |n| { + if (n >= max) return treecount + 1; + treecount += 1; + } + return treecount; +} + +fn view_distance_up(pos: [2]usize, grid: [99][99]u8) u32 { + var max = grid[pos[0]][pos[1]]; + var treecount: u8 = 0; + var i: usize = pos[0]; + while (i > 0) : (treecount += 1) { + i -= 1; + if (grid[i][pos[1]] >= max) return treecount + 1; + } + return treecount; +} + +fn view_distance_left(pos: [2]usize, grid: [99][99]u8) u32 { + var max = grid[pos[0]][pos[1]]; + var treecount: u8 = 0; + var i: usize = pos[1]; + while (i > 0) : (treecount += 1) { + i -= 1; + if (grid[pos[0]][i] >= max) return treecount + 1; + } + return treecount; +} diff --git a/inputs/day_08 b/inputs/day_08 new file mode 100644 index 0000000..590022d --- /dev/null +++ b/inputs/day_08 @@ -0,0 +1,100 @@ +100221200032023210231132410224121421011444302143121341425413411104320412140011030313333000220101112 +112202123021003133332142233323404332315445153153433313154424232233100410424422313323031220233011010 +011002203101130221201112041212404433424255343232213155531144333552214422033044404110303133013102011 +121111233130221221224141101130304514242212243115142242515311345141411232002244120020312220212230110 +202100121002031143312404331332151115114223331225243515233534114435141142242331404201300323113201222 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} } }, }; pub fn main() !void { |