assert (k > 0); while (--k > 0) { struct tavl_node *y = pa[k]; if (da[k] == 0) { y->tavl_balance++; if (y->tavl_balance == +1) break; else if (y->tavl_balance == +2) { struct tavl_node *x = y->tavl_link[1]; assert (x != NULL); if (x->tavl_balance == -1) { struct tavl_node *w; assert (x->tavl_balance == -1); w = x->tavl_link[0]; x->tavl_link[0] = w->tavl_link[1]; w->tavl_link[1] = x; y->tavl_link[1] = w->tavl_link[0]; w->tavl_link[0] = y; if (w->tavl_balance == +1) x->tavl_balance = 0, y->tavl_balance = -1; else if (w->tavl_balance == 0) x->tavl_balance = y->tavl_balance = 0; else /* |w->tavl_balance == -1| */ x->tavl_balance = +1, y->tavl_balance = 0; w->tavl_balance = 0; if (w->tavl_tag[0] == TAVL_THREAD) { y->tavl_tag[1] = TAVL_THREAD; y->tavl_link[1] = w; w->tavl_tag[0] = TAVL_CHILD; } if (w->tavl_tag[1] == TAVL_THREAD) { x->tavl_tag[0] = TAVL_THREAD; x->tavl_link[0] = w; w->tavl_tag[1] = TAVL_CHILD; } pa[k - 1]->tavl_link[da[k - 1]] = w; } else if (x->tavl_balance == 0) { y->tavl_link[1] = x->tavl_link[0]; x->tavl_link[0] = y; x->tavl_balance = -1; y->tavl_balance = +1; pa[k - 1]->tavl_link[da[k - 1]] = x; break; } else /* |x->tavl_balance == +1| */ { if (x->tavl_tag[0] == TAVL_CHILD) y->tavl_link[1] = x->tavl_link[0]; else { y->tavl_tag[1] = TAVL_THREAD; x->tavl_tag[0] = TAVL_CHILD; } x->tavl_link[0] = y; x->tavl_balance = y->tavl_balance = 0; pa[k - 1]->tavl_link[da[k - 1]] = x; } } } else { y->tavl_balance--; if (y->tavl_balance == -1) break; else if (y->tavl_balance == -2) { struct tavl_node *x = y->tavl_link[0]; assert (x != NULL); if (x->tavl_balance == +1) { struct tavl_node *w; assert (x->tavl_balance == +1); w = x->tavl_link[1]; x->tavl_link[1] = w->tavl_link[0]; w->tavl_link[0] = x; y->tavl_link[0] = w->tavl_link[1]; w->tavl_link[1] = y; if (w->tavl_balance == -1) x->tavl_balance = 0, y->tavl_balance = +1; else if (w->tavl_balance == 0) x->tavl_balance = y->tavl_balance = 0; else /* |w->tavl_balance == +1| */ x->tavl_balance = -1, y->tavl_balance = 0; w->tavl_balance = 0; if (w->tavl_tag[0] == TAVL_THREAD) { x->tavl_tag[1] = TAVL_THREAD; x->tavl_link[1] = w; w->tavl_tag[0] = TAVL_CHILD; } if (w->tavl_tag[1] == TAVL_THREAD) { y->tavl_tag[0] = TAVL_THREAD; y->tavl_link[0] = w; w->tavl_tag[1] = TAVL_CHILD; } pa[k - 1]->tavl_link[da[k - 1]] = w; } else if (x->tavl_balance == 0) { y->tavl_link[0] = x->tavl_link[1]; x->tavl_link[1] = y; x->tavl_balance = +1; y->tavl_balance = -1; pa[k - 1]->tavl_link[da[k - 1]] = x; break; } else /* |x->tavl_balance == -1| */ { if (x->tavl_tag[1] == TAVL_CHILD) y->tavl_link[0] = x->tavl_link[1]; else { y->tavl_tag[0] = TAVL_THREAD; x->tavl_tag[1] = TAVL_CHILD; } x->tavl_link[1] = y; x->tavl_balance = y->tavl_balance = 0; pa[k - 1]->tavl_link[da[k - 1]] = x; } } } }