irb(main):016:0> n = 4 => 4 irb(main):017:0> table = (1..n).to_a.zip(Array.new(n, Array.new)).to_h => {1=>[], 2=>[], 3=>[], 4=>[]} irb(main):018:0> table[1] << 1 => [1] irb(main):019:0> table => {1=>[1], 2=>[1], 3=>[1], 4=>[1]} irb(main):…