start with the linked list whose head data is the least
if ( h1 . data < h2 . data ) : NEW_LINE INDENT h1 . next = merge ( h1 . next , h2 ) NEW_LINE return h1 NEW_LINE DEDENT else : NEW_LINE INDENT h2 . next = merge ( h1 , h2 . next ) NEW_LINE return h2 NEW_LINE DEDENT