if top ' s ▁ left ▁ and ▁ right ▁ child ▁ ▁ ▁ exists , ▁ then ▁ push ▁ them ▁ to ▁ ' q '
if ( top . left != null ) q . Enqueue ( top . left ) ; if ( top . right != null ) q . Enqueue ( top . right ) ; } } }