408556: GYM103185 M May I Add a Letter?

You have a string $$$S$$$ of length $$$N$$$ and you are asked to perform a sequence of $$$Q$$$ updates of two types to $$$S$$$:

• Append a given character to the end of $$$S$$$.
• Delete the last character from $$$S$$$.

Initially and after each update, you must calculate the number of distinct strings that occur at least twice as substrings of $$$S$$$.

For example, if $$$S$$$ is initially "ABABC", the answer is $$$3$$$, as "A", "B" and "AB" occur twice as substrings of $$$S$$$. If you are asked to append the character "$$$\texttt{C}$$$", $$$S$$$ will become "ABABCC" and the answer will be $$$4$$$, as now "C" occurs twice too. If you are asked to append "$$$\texttt{C}$$$" again, $$$S$$$ will be "ABABCCC" and the answer will be $$$5$$$, as "CC" occurs twice now. If you are given a delete operation now, $$$S$$$ will become "ABABCC" and the answer will be $$$4$$$ again.

The first line contains a string $$$S$$$ of length $$$N$$$ ($$$1 \leq N \leq 10^5$$$), indicating the initial value of the string. Each character of $$$S$$$ is an uppercase letter. The second line contains a string $$$U$$$ of length $$$Q$$$ ($$$1 \leq Q \leq 10^5$$$), representing the updates to perform. Each character of $$$U$$$ is either an uppercase letter indicating that such a letter must be appended, or the character "$$$\texttt{-}$$$" (hyphen) denoting a delete operation. The updates must be applied in the order they appear in $$$U$$$. It is guaranteed that delete operations are not applied to empty strings.

Output $$$Q+1$$$ lines, each line with an integer indicating the number of distinct strings that occur at least twice as substrings of $$$S$$$. Line $$$1$$$ refers to the initial value of $$$S$$$, while line $$$i+1$$$ refers to the value of $$$S$$$ after applying the first $$$i$$$ updates ($$${i}={1}, {2}, \ldots, {Q}$$$).

ABABC
CC-

3
4
5
4

ABAB
A--CC

3
5
3
1
1
2

HAVE
FUN

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