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## B - Permutation Check Editorial by en_translator

One can check if each of $$1, 2, 3, \dots, N$$ as an element of $$A$$ to solve in a total of $$O(N)$$ time time.

Sample code (C++)

Otherwise, one can sort the elements of $$A$$ in the increasing order and check if $$1, 2, \dots, N$$ are in this order to solve in a total of $$O (N \log N)$$ time.

Sample code (C++)

Sample code (Python)

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