for splay_each(node_t, n, node_tree) {
if(n->status.visited != n->status.reachable) {
n->status.reachable = !n->status.reachable;
for splay_each(node_t, n, node_tree) {
if(n->status.visited != n->status.reachable) {
n->status.reachable = !n->status.reachable;