Hash different postures:
- Brackets minimum sequence tree representation of s [i]
If i is a leaf node :()
If the child node i is j1 ~ jn: (s [j1] ... s [jn]), attention s [j] to be arranged in lexicographic order
If i is a leaf node :()
If the child node i is j1 ~ jn: (s [j1] ... s [jn]), attention s [j] to be arranged in lexicographic order