void access(splay* ov) {
for(splay *w = ov, *v = ov; w != NULL; v = w, w = w->path_up) {
do_splay(w);
if(w->sons[1]) w->sons[1]->path_up = w, w->sons[1]->up = NULL;
if(w != v) w->sons[1] = v, v->up = w, v->path_up = NULL;
else w->sons[1] = NULL;
}
do_splay(ov);
}
struct splaytree_node *splaytree_lookup(const struct splaytree_node *key,
struct splaytree *tree)
{
if (!tree->root)
return NULL;
if (do_splay(key, tree) != 0)
return NULL;
return tree->root;
}
void splaytree_remove(struct splaytree_node *node, struct splaytree *tree)
{
struct splaytree_node *right, *left, *prev;
do_splay(node, tree);
assert(tree->root == node); /* 'node' must be present */
right = get_right(node);
left = get_left(node);
if (!left) {
tree->root = right;
tree->first = splaytree_next(node);
prev = NULL;
} else {
tree->root = left;
do_splay(node, tree);
set_right(right, tree->root);
prev = tree->root;
}
if (right)
set_prev(prev, get_first(right));
else
tree->last = prev;
}
struct splaytree_node *splaytree_insert(struct splaytree_node *node,
struct splaytree *tree)
{
struct splaytree_node *root = tree->root;
int res;
if (!root) {
INIT_NODE(node);
tree->root = node;
tree->first = node;
tree->last = node;
return NULL;
}
res = do_splay(node, tree);
if (res == 0)
return tree->root;
root = tree->root;
if (res < 0) {
struct splaytree_node *left = get_left(root);
set_left(left, node);
set_right(root, node);
if (left)
set_next(node, get_last(left));
else
tree->first = node;
set_prev(node, root);
} else {
struct splaytree_node *right = get_right(root);
set_right(right, node);
set_left(root, node);
if (right)
set_prev(node, get_first(right));
else
tree->last = node;
set_next(node, root);
}
tree->root = node;
return NULL;
}
int lca(int v, int w) {
access(&vtxs[v]); access(&vtxs[w]); do_splay(&vtxs[v]);
if(vtxs[v].path_up == NULL) return v;
return vtxs[v].path_up - vtxs;
}
splay* find(int v) {
splay* s = &vtxs[v];
access(s); while(s->sons[0]) s = s->sons[0]; do_splay(s);
return s;
}