vertices, @max_cats_number = gets.split.map(&:to_i)
@cats_positions = gets.split.map(&:to_i)
@tree = Array.new(vertices + 1){ Array.new }
 
(vertices - 1).times do
  from, to = gets.split.map(&:to_i)
  from = from - 1
  to = to - 1
  @tree[from] << to
  @tree[to] << from
end
 
def graph(current_vertice, last_vertice, cats_number)
 
  sum = 0
 
  if cats_number > @max_cats_number
    return 0
  elsif @tree[current_vertice].length == 1 && @tree[current_vertice][0] == last_vertice
    return 1
  end
 
  for i in 0...@tree[current_vertice].length
    if @tree[current_vertice][i] != last_vertice
      if @cats_positions[@tree[current_vertice][i]] == 1
        sum = sum + graph(@tree[current_vertice][i], current_vertice, cats_number + 1)
      else
        sum = sum + graph(@tree[current_vertice][i], current_vertice, 0)
      end
    end
  end
 
  return sum
end
 
puts graph(0, -1, @cats_positions[0])
 

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

NCAxCjEgMSAwIDAKMSAyCjEgMwoxIDQ=

4 1
1 1 0 0
1 2
1 3
1 4