Editorial for Singularity Cup P1 - Maximum Permutation Product - Olympiads Online Judge

Editorial for Singularity Cup P1 - Maximum Permutation Product

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Author: Mystical

Subtask 1

We can compute the value of every possible subarray and determine which one yields the highest value.

Time complexity: $\mathcal{O}(N^2)$ ~\mathcal{O}(N^2)~

Subtask 2

When $N \ge 4$ ~N \ge 4~, it is always optimal to include the entire array excluding $1$ ~1~ if $A_1 = 1$ ~A_1 = 1~ or $A_N = 1$ ~A_N = 1~.

$N = 3$ ~N = 3~ is an edge case where choosing the subarray that only contains the element $3$ ~3~ is always optimal.

Time complexity: $\mathcal{O}(N)$ ~\mathcal{O}(N)~

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