Odd Even Sort

AtCoder

IDarc121_c

Time2000ms

Memory256MB

Difficulty—

Given is a sequence $p$ which is a permutation of $(1,2, \ldots, N)$. Initially, the $n$\-th term of $p$ is $p_{n}$. Your objective is to sort $p$ in ascending order in at most $N^2$ _operations_. In one operation, you make the following change on $p$: * In the $1$\-st, $3$\-rd, and subsequent **odd-numbered** operations, you choose an **odd number** $n$ between $1$ and $N-1$ (inclusive) to swap $p_n$ and $p_{n+1}$. * In the $2$\-nd, $4$\-th, and subsequent **even-numbered** operations, you choose an **even number** $n$ between $2$ and $N-1$ (inclusive) to swap $p_n$ and $p_{n+1}$. We can prove that the objective is always achievable under the Constraints of this problem. Find one sequence of operations that achieves the objective. You will be given $T$ test cases and asked to solve each of them. ## Constraints * All values in input are integers. * $1 \leq T \leq 250$ * $2 \leq N \leq 500$ * $1 \leq p_i \leq N$ * $p$ is a permutation of $(1,2,\ldots,N)$. * In one input file, the sum of $N$ does not exceed $500$. ## Input Input is given from Standard Input in the following format: $T$ $\mathrm{case}_{1}$ $\vdots$ $\mathrm{case}_{T}$ Each case is in the following format: $N$ $p_1$ $\cdots$ $p_N$ [samples]

Samples

Input #1

Output #1

2
1 4
0

*   Here is the description for the $1$\-st test case.
    *   Choosing $1$ in the $1$\-st operation makes $p = (1,2,3,5,4)$.
    *   Choosing $4$ in the $2$\-nd operation makes $p = (1,2,3,4,5)$.
    *   Note that although $(1,4)$ is a valid sequence of operations, $(4, 1)$ is not.
*   Also note that it is allowed to perform no operation, and it is not required to minimize the number of operations.

API Response (JSON)

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      "content": "Given is a sequence $p$ which is a permutation of $(1,2, \\ldots, N)$. Initially, the $n$\\-th term of $p$ is $p_{n}$. Your objective is to sort $p$ in ascending order in at most $N^2$ _operations_. In ",
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      "statement_type": "Markdown",
      "content": "Given is a sequence $p$ which is a permutation of $(1,2, \\ldots, N)$. Initially, the $n$\\-th term of $p$ is $p_{n}$.\nYour objective is to sort $p$ in ascending order in at most $N^2$ _operations_. In ...",
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