Submission #1515971

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Source Code Expand

n, m = gets.not_nil!.split.map(&.to_i)
edges = Array.new(m) do
  a, b, c = gets.not_nil!.split
  {a.to_i - 1, b.to_i - 1, -(c.to_i64)}
end
INF = Int64::MAX
d = Array.new(n, INF)
d[0] = 0_i64
n.times do
  edges.each do |e|
    next if d[e[0]] == INF
    if d[e[0]] + e[2] < d[e[1]]
      d[e[1]] = d[e[0]] + e[2]
    end
  end
end
ans = -d[n - 1]
n.times do
  edges.each do |e|
    next if d[e[0]] == INF
    if d[e[0]] + e[2] < d[e[1]]
      d[e[1]] = d[e[0]] + e[2]
    end
  end
end
puts ans == -d[n - 1] ? ans : "inf"

Submission Info

Judge Result