day 4

src/day_4.jl

@@ -0,0 +1,76 @@
+include(joinpath(readchomp(`git rev-parse --show-toplevel`), "aoc.jl"))
+import .Aoc: @aoc
+using Pipe: @pipe
+
+function read_boards(input)
+  in = filter(!=(""), input)
+  boards = []
+  for i in 1:5:length(in)
+    board = []
+    for x in 0:4
+      row = @pipe split(in[i+x], " ") |> filter(!=(""), _) |> parse.(Int, _)
+      push!(board, row)
+    end
+    push!(boards, vcat(board...))
+  end
+
+  return boards
+end
+
+function mark_board(board, n)
+  idx = findall(==(n), board)
+  for i in idx
+    board[i] = -1
+  end
+end
+
+function is_winner(board)
+  for i in 1:5:length(board)
+    if unique(board[i:i+4]) == [-1]
+      return true
+    end
+  end
+
+  for x in 1:5
+    if unique(board[x:5:length(board)]) == [-1]
+      return true
+    end
+  end
+  return false
+end
+
+function score(board, n)
+  sum(filter(!=(-1), board)) * n
+end
+
+function scores(numbers, boards)
+  scores = []
+  winners = []
+  for n in numbers
+    for (i, board) in enumerate(boards)
+      i in winners ? continue : mark_board(board, n)
+      if is_winner(board)
+        push!(winners, i)
+        push!(scores, score(board, n))
+      end
+    end
+  end
+  return scores
+end
+
+function p1(input::Vector{String})
+  numbers = @pipe split(input[1], ",") |> parse.(Int, _)
+
+  boards = read_boards(input[3:end])
+  return scores(numbers, boards)[1]
+end
+
+
+function p2(input::Vector{String})
+  numbers = @pipe split(input[1], ",") |> parse.(Int, _)
+
+  boards = read_boards(input[3:end])
+  return scores(numbers, boards)[end]
+end
+
+@aoc(2021, 4)