assert (x->avl_balance == +1); w = x->avl_link[1]; x->avl_link[1] = w->avl_link[0]; w->avl_link[0] = x; y->avl_link[0] = w->avl_link[1]; w->avl_link[1] = 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;