C - Previous Permutation Editorial by Kiri8128
As \(N\) is not very large, we can calculate the ID of \(P\) directly. If we prepare “kth_permutation” and “id_of_permutation” functions beforehand, the problem is almost trivial. Arbitrary-precision integer calculation (like in Python) would be helpful because IDs may not be very small.
AC コード (PyPy3)
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