Submission #851052

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Source Code Expand

def read_numbers; gets.split.map(&:to_i); end
N, = read_numbers
CONNECTED = Hash.new{|h, k| h[k] = []}
(N-1).times do
  a, b = read_numbers
  CONNECTED[a] << b
  CONNECTED[b] << a
end

def solve(i, from)
  b = w = 1
  CONNECTED[i].each do |j|
    next if j == from
    bb, ww = solve(j, i)
    b *= ww
    w *= (bb+ww)
  end
  return [b, w]
end

b, w = solve(1, nil)
p((b + w) % (10**9+7))

Submission Info

Judge Result