Submission #2757184

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Source Code Expand

N, X = gets.split.map(&:to_i)
edges = Array.new(N){{}}
(N-1).times do |i|
    x, y, c = gets.split.map(&:to_i)
    edges[x-1][y-1] = c
    edges[y-1][x-1] = c
end

values = Array.new(N)
values[0] = 0
stack = [0]
while stack.length > 0
    i = stack.pop
    edges[i].each do |j, c|
        next if values[j]
        values[j] = values[i] ^ c
        stack.push(j)
    end
end

histo = Hash.new(0)
values.each do |v|
    histo[v] += 1
end

ans = 0
histo.each do |k, v|
    ans += histo[k] * histo[k^X]
end
ans -= N if X == 0
puts ans/2

Submission Info

Judge Result