day 5

src/day_5.jl

@@ -0,0 +1,51 @@
+include(joinpath(readchomp(`git rev-parse --show-toplevel`), "aoc.jl"))
+import .Aoc: @aoc
+using Pipe: @pipe
+
+function parse_line(input)
+	c = match(r"(\d+),(\d+) -> (\d+),(\d+)", input).captures
+	return parse.(Int, c)
+end
+
+function p1(input::Vector{String})
+	board = Dict{Tuple{Int64, Int64}, Int64}()
+	for l in input
+		p = parse_line(l)
+		if p[1] == p[3] || p[2] == p[4]
+			xstep = p[1] > p[3] ? -1 : 1
+			ystep = p[2] > p[4] ? -1 : 1
+			for x in p[1]:xstep:p[3]
+				for y in p[2]:ystep:p[4]
+					(x,y) in keys(board) ? (board[(x,y)] += 1) : (board[(x,y)] = 1)
+				end
+			end
+		end
+	end
+	return count(>=(2), values(board))
+end
+
+
+function p2(input::Vector{String})
+	board = Dict{Tuple{Int64, Int64}, Int64}()
+	for l in input
+		p = parse_line(l)
+		if p[1] == p[3] || p[2] == p[4]
+			xstep = p[1] > p[3] ? -1 : 1
+			ystep = p[2] > p[4] ? -1 : 1
+			for x in p[1]:xstep:p[3]
+				for y in p[2]:ystep:p[4]
+					(x,y) in keys(board) ? (board[(x,y)] += 1) : (board[(x,y)] = 1)
+				end
+			end
+		elseif abs(p[1] - p[3]) == abs(p[2] - p[4])
+			xstep = p[1] > p[3] ? -1 : 1
+			ystep = p[2] > p[4] ? -1 : 1
+			for(x,y) in zip(p[1]:xstep:p[3], p[2]:ystep:p[4])
+				(x,y) in keys(board) ? (board[(x,y)] += 1) : (board[(x,y)] = 1)
+			end
+		end
+	end
+	return count(>=(2), values(board))
+end
+
+@aoc(2021, 5)