Node index:      0	State: NEW
----------------------------------------
Node index:      0	State: SEEN ONCE
----------------------------------------
Node index:      1	State: NEW
----------------------------------------
Node index:      2	State: NEW
Node index:      1	State: SEEN ONCE
----------------------------------------
Node index:      2	State: SEEN ONCE
Node index:      1	State: SEEN ONCE
----------------------------------------
Node index:      3	State: NEW
Node index:      1	State: SEEN ONCE
----------------------------------------
Node index:      3	State: SEEN ONCE
Node index:      1	State: SEEN ONCE
----------------------------------------
Node index:      4	State: NEW
Node index:      1	State: SEEN ONCE
----------------------------------------
Node index:      4	State: SEEN ONCE
Node index:      1	State: SEEN ONCE
----------------------------------------
Node index:      1	State: SEEN ONCE
----------------------------------------
Preorder traversal:
Node index:      0	Value: 23
Node index:      2	Value: 22
Node index:      3	Value: 4
Node index:      4	Value: 2
Node index:      1	Value: 6

