#P11571. Count Integer Pairs with Bitwise Constraints
Count Integer Pairs with Bitwise Constraints
Count Integer Pairs with Bitwise Constraints
Given a binary string (r) (with no leading zeros) and two integers (m) and (s), count the number of pairs of integers ((fi, sh)) satisfying:
\begin{enumerate} \item (0 \le fi \le sh \le r), where (r) is interpreted as its decimal value given in binary form. \item (\operatorname{popcount}(fi \oplus sh) = m), where (\oplus) denotes the bitwise XOR operation and (\operatorname{popcount}(x)) is the number of ones in the binary representation of (x). \item (\operatorname{popcount}(fi + sh) = s). \end{enumerate}
Output the answer modulo (998244353).
inputFormat
The input consists of a single line containing the binary string (r) and two integers (m) and (s) separated by spaces. It is guaranteed that (r) does not contain any leading zeros.
outputFormat
Output a single integer, which is the number of valid pairs ((fi, sh)) modulo (998244353).
sample
10 1 1
4