help on hacking hash

Revision en1, by tril0713, 2024-01-24 12:41:26
Problem statement

We transform the condition $$$s_i \ne s_{n-i+1}$$$ into if we change all $$$\texttt{0} \to \texttt{1},\texttt{1} \to \texttt{0}$$$ and reverse it to get a string $$$t$$$, $$$s$$$ is good if and only if $$$s = t$$$. Then we can use suffix array or manachar to get the answer.

Then, the hash solution did the same transformation and use hashing to get the answer with $$$\text{base} = 10^9+7$$$ and $$$\text{mod} = 2^{64}-1$$$ (unsigned long long). Can it be hacked? I have done stress test for $$$15000$$$ test cases :(

I will provide the hash code and the suffix array code below, if you need to make a stress test.

SA code
hash code

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en1 English tril0713 2024-01-24 12:41:26 3652 Initial revision (published)