Submission #1519020

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Source Code Expand

def dfs(cur, depth, visited, graph)
  return 1 if depth == visited.size
  ret = 0
  visited.size.times do |i|
    next if visited[i]
    next if !graph[cur][i]
    visited[i] = true
    ret += dfs(i, depth + 1, visited, graph)
    visited[i] = false
  end
  ret
end

n, m = gets.not_nil!.split.map(&.to_i)
g = Array.new(n) { Array.new(n, false) }
m.times do
  a, b = gets.not_nil!.split.map { |s| s.to_i - 1 }
  g[a][b] = g[b][a] = true
end
visited = Array.new(n, false)
visited[0] = true
puts dfs(0, 1, visited, g)

Submission Info

Judge Result