Why the answer is 16 but not 8 in Example 1? I can only figure out the 8 strings below
- B AAAAAAA ABBABAB
- B AAAAAAA ABBABBA
- B AAAAAAA ABABBAB
- B AAAAAAA ABABBBA
- B ABBABAB AAAAAAA
- B ABBABBA AAAAAAA
- B ABABBAB AAAAAAA
- B ABABBBA AAAAAAA
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I think you misinterpreted $$$s_i$$$ and the input. I recommend reading the definition of $$$s_i$$$ and the input again. "B ABBABAB AAAAAAA" is not a valid constellation. The children of $$$s_1$$$ are $$$s_2$$$ and $$$s_3$$$, not $$$s_2$$$ and $$$s_9$$$.
What could've lead to this confusion: The preorder string of input "BAAAAAAAABBABAB" is not "BAAAAAAAABBABAB".
oh, thank you for explaining it to me, i've been confused about this for hours..