Counting Zigzag Sequences

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Given an array A1, A2, ..., AN of integers, count number of "Zig-zag" sub-sequences in it. A sub-sequence of array A is obtained by deleting greater than or equal to zero elements and preserving the order of remaining elements. So, a sub-sequence of length K can by defined by a sequence of indices b1, b2, ..., bK such that 1 ≤ b1 2 K ≤ N. A "Zig-zag" sequence is a sub-subsequence of odd length a

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solution.cppC++17

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