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