Alternating Permutations

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You are given K indices, A[1], A[2], ... , A[K]. A[1] A[1] = 1 and A[K] = N. A permutation of the numbers between 1 and N is called valid if : The numbers in the permutation between indices A[1] and A[2] (inclusive) form an increasing sequence, the numbers in the permutation between indices A[2] and A[3] (inclusive) form a decreasing sequence, those between A[3] and A[4] (inclusive) form an increa

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solution.cppC++17

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