Permutation Subsequence

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Chefina has an array $A$ consisting of $N$ positive integers. A permutation subsequence of length $M$ is a subsequence that represents a permutation of length $M$. Now, Chefina asks Chef to find the count of permutation subsequences in array $A$. The count can be very large, so output it modulo $1000000007$ $(10^9 + 7)$. As a reminder: - A subsequence of an array is obtained by deleting some (

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solution.cppC++17

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