Function tree_mem_sort::sort_dag

pub fn sort_dag<T, P, C>(nodes: &mut [T], parents: P, children: C) where
    P: Fn(&mut T) -> &mut [usize],
    C: Fn(&mut T) -> &mut [usize], 

The same algorithm as sort, but for Directed Acyclic Graphs (DAGs), encoded as trees with shared nodes.

WARNING: To avoid an infinite loop, one must be careful about the order of children. E.g. if A has children C, B and B has child C, then the tree is not a DAG. This is because the order of children is preserved after sorting.