Developer Shares O(1) Space Method for Alternating Array Rearrangement Problem

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A developer has proposed an alternative solution to the classic 'Rearrange Array Alternately' problem, commonly found on platforms like LeetCode and GeeksforGeeks. The technique, dubbed Sequential Suffix Reversal, works by repeatedly reversing shrinking suffixes of a sorted array in place until elements settle into a max-min alternating order. Unlike the standard modulo math trick, this approach uses only in-place pointer swaps and requires no extra memory, achieving O(1) space complexity. However, the method runs in O(N²) time, making it slower than existing optimal solutions and likely to fail time limits on large competitive programming inputs. The author presents it not as a superior algorithm, but as a structurally intuitive alternative worth knowing for algorithm-design discussions.

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ProgrammingDEV Community ·

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ProgrammingDEV Community ·

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