assert (x->avl_balance == -1); w = x->avl_link[0]; x->avl_link[0] = w->avl_link[1]; w->avl_link[1] = x; y->avl_link[1] = w->avl_link[0]; w->avl_link[0] = y; if (w->avl_balance == +1) x->avl_balance = 0, y->avl_balance = -1; else if (w->avl_balance == 0) x->avl_balance = y->avl_balance = 0; else /* |w->avl_balance == -1| */ x->avl_balance = +1, y->avl_balance = 0; w->avl_balance = 0;