Obtain forest out of tree with even number of nodes

Question

I\'m stuck on a code challenge, and I want a hint.

PROBLEM: You are given a tree data structure (without cycles) and are asked to remo

Answer 1

Solution - Traverse all the edges, and count the number of even edges

If we remove an edge from the tree and it results in two tree with even number of vertices, let's call that edge - even edge

If we remove an edge from the tree and it results in two trees with odd number of vertices, let's call that edge - odd edge

Here is my solution in Ruby

num_vertices, num_edges = gets.chomp.split(' ').map { |e| e.to_i }
graph = Graph.new
(1..num_vertices).to_a.each do |vertex|
  graph.add_node_by_val(vertex)
end

num_edges.times do |edge|
  first, second = gets.chomp.split(' ').map { |e| e.to_i }
  graph.add_edge_by_val(first, second, 0, false)
end

even_edges = 0
graph.edges.each do |edge|
  dup = graph.deep_dup
  first_tree = nil
  second_tree = nil
  subject_edge = nil
  dup.edges.each do |e|
    if e.first.value == edge.first.value && e.second.value == edge.second.value
      subject_edge = e
      first_tree = e.first
      second_tree = e.second
    end
  end
  dup.remove_edge(subject_edge)
  if first_tree.size.even? && second_tree.size.even?
    even_edges += 1
  end
end
puts even_edges

Note - Click Here to check out the code for Graph, Node and Edge classes