A16271 | Cyclic MEX

For an array $a$ , define its cost as $\sum_{i=1}^{n} \operatorname{mex} ^\dagger ([a_1,a_2,\ldots,a_i])$ .

You are given a permutation $^\ddagger$ $p$ of the set $\{0,1,2,\ldots,n-1\}$ . Find the maximum cost across all cyclic shifts of $p$ .

$^\dagger\operatorname{mex}([b_1,b_2,\ldots,b_m])$ is the smallest non-negative integer $x$ such that $x$ does not occur among $b_1,b_2,\ldots,b_m$ .

$^\ddagger$ A permutation of the set $\{0,1,2,...,n-1\}$ is an array consisting of $n$ distinct integers from $0$ to $n-1$ in arbitrary order. For example, $[1,2,0,4,3]$ is a permutation, but $[0,1,1]$ is not a permutation ( $1$ appears twice in the array), and $[0,2,3]$ is also not a permutation ( $n=3$ but there is $3$ in the array).

Each test consists of multiple test cases. The first line contains a single integer $t$ ( $1 \le t \le 10^5$ ) — the number of test cases. The description of the test cases follows.

The first line of each test case contains a single integer $n$ ( $1 \le n \le 10^6$ ) — the length of the permutation $p$ .

The second line of each test case contain $n$ distinct integers $p_1, p_2, \ldots, p_n$ ( $0 \le p_i < n$ ) — the elements of the permutation $p$ .

It is guaranteed that sum of $n$ over all test cases does not exceed $10^6$ .

For each test case, output a single integer — the maximum cost across all cyclic shifts of $p$ .