if (y->pavl_balance == -2) { struct pavl_node *x = y->pavl_link[0]; if (x->pavl_balance == -1) { w = x; y->pavl_link[0] = x->pavl_link[1]; x->pavl_link[1] = y; x->pavl_balance = y->pavl_balance = 0; x->pavl_parent = y->pavl_parent; y->pavl_parent = x; if (y->pavl_link[0] != NULL) y->pavl_link[0]->pavl_parent = y; } else { assert (x->pavl_balance == +1); w = x->pavl_link[1]; x->pavl_link[1] = w->pavl_link[0]; w->pavl_link[0] = x; y->pavl_link[0] = w->pavl_link[1]; w->pavl_link[1] = y; if (w->pavl_balance == -1) x->pavl_balance = 0, y->pavl_balance = +1; else if (w->pavl_balance == 0) x->pavl_balance = y->pavl_balance = 0; else /* |w->pavl_balance == +1| */ x->pavl_balance = -1, y->pavl_balance = 0; w->pavl_balance = 0; w->pavl_parent = y->pavl_parent; x->pavl_parent = y->pavl_parent = w; if (x->pavl_link[1] != NULL) x->pavl_link[1]->pavl_parent = x; if (y->pavl_link[0] != NULL) y->pavl_link[0]->pavl_parent = y; } } else if (y->pavl_balance == +2) { struct pavl_node *x = y->pavl_link[1]; if (x->pavl_balance == +1) { w = x; y->pavl_link[1] = x->pavl_link[0]; x->pavl_link[0] = y; x->pavl_balance = y->pavl_balance = 0; x->pavl_parent = y->pavl_parent; y->pavl_parent = x; if (y->pavl_link[1] != NULL) y->pavl_link[1]->pavl_parent = y; } else { assert (x->pavl_balance == -1); w = x->pavl_link[0]; x->pavl_link[0] = w->pavl_link[1]; w->pavl_link[1] = x; y->pavl_link[1] = w->pavl_link[0]; w->pavl_link[0] = y; if (w->pavl_balance == +1) x->pavl_balance = 0, y->pavl_balance = -1; else if (w->pavl_balance == 0) x->pavl_balance = y->pavl_balance = 0; else /* |w->pavl_balance == -1| */ x->pavl_balance = +1, y->pavl_balance = 0; w->pavl_balance = 0; w->pavl_parent = y->pavl_parent; x->pavl_parent = y->pavl_parent = w; if (x->pavl_link[0] != NULL) x->pavl_link[0]->pavl_parent = x; if (y->pavl_link[1] != NULL) y->pavl_link[1]->pavl_parent = y; } } else return &n->pavl_data; if (w->pavl_parent != NULL) w->pavl_parent->pavl_link[y != w->pavl_parent->pavl_link[0]] = w; else tree->pavl_root = w; return &n->pavl_data;