Primitive Ruby Disjoint-Set

dsu.rb

class DSU

  def initialize(x)
    @array = Array.new(x) {|i| i }
  end

  def find(x)
    return x if @array[x] == x
    @array[x] = find(@array[x])
  end

  def union(a, b)
    @array[find(a)] = @array[find(b)]
  end

  def sets
    @array.collect{ |i| find(i) }.uniq.length
  end
  
end