map = Array(Array(Array(Int32))).new(301) { |i| Array(Array(Int32)).new(301) { |j| Array(Int32).new(301, 0) } }

pairs = (1..300).to_a.product (1..300).to_a
(1..300).each do |y|
  (1..300).each do |x|
    rack_id = x + 10
    level = rack_id * y
    level += 3463
    level *= rack_id
    digit = (level / 100) % 10
    digit -= 5

    map[x][y][1] = digit
  end
end

def square_score(powers, coord, size)
  x, y = coord
  total = 0
  half = size / 2

  total = powers[x][y][half] +
    powers[x][y + half][half] +
    powers[x + half][y][half] +
    powers[x + half][y + half][half]

  if size.odd?
    size.times do |i|
      total += powers[x + size - 1][y + i][1]
      total += powers[x + i][y + size - 1][1]
    end
    total -= powers[x + size - 1][y + size - 1][1]
  end

  powers[x][y][size] = total
  return total
end

def max_score(powers, pairs, size = 3)
  possible_squares = (1..300 - size + 1).to_a
  possible_pairs = possible_squares.product possible_squares
  
  possible_pairs.max_by do |pair|
    x, y = pair
    score = square_score(powers, pair, size)
  end
end

puts max_score(map, pairs, 2)
puts max_score(map, pairs, 3)

max = -1000
max_pair = nil
297.times do |i|
  pair = max_score(map, pairs, i + 4)
  score = square_score(map, pair, i + 4)
  if score > max
    max = score
    max_pair = { pair, i + 4 }
  else
    break
  end
end
puts max_pair