Exoswap

AtCoder

IDarc110_c

Time2000ms

Memory256MB

Difficulty—

We have a permutation $P = P_1, P_2, \ldots, P_N$ of $1, 2, \ldots, N$. You have to do the following $N - 1$ operations on $P$, **each exactly once**, in some order: * Swap $P_1$ and $P_2$. * Swap $P_2$ and $P_3$. $\vdots$ * Swap $P_{N-1}$ and $P_N$. Your task is to sort $P$ in ascending order by configuring the order of operations. If it is impossible, print `-1` instead. ## Constraints * All values in input are integers. * $2 \leq N \leq 2 \times 10^5$ * $P$ is a permutation of $1, 2, \ldots, N$. ## Input Input is given from Standard Input in the following format: $N$ $P_1$ $P_2$ $\ldots$ $P_N$ [samples]

Samples

Input #1

5
2 4 1 5 3

Output #1

4
2
3
1

The following sequence of operations sort $P$ in ascending order:

*   First, swap $P_4$ and $P_5$, turning $P$ into $2, 4, 1, 3, 5$.
*   Then, swap $P_2$ and $P_3$, turning $P$ into $2, 1, 4, 3, 5$.
*   Then, swap $P_3$ and $P_4$, turning $P$ into $2, 1, 3, 4, 5$.
*   Finally, swap $P_1$ and $P_2$, turning $P$ into $1, 2, 3, 4, 5$.

Input #2

5
5 4 3 2 1

Output #2

\-1

API Response (JSON)

{
  "problem": {
    "name": "Exoswap",
    "description": {
      "content": "We have a permutation $P = P_1, P_2, \\ldots, P_N$ of $1, 2, \\ldots, N$. You have to do the following $N - 1$ operations on $P$, **each exactly once**, in some order: *   Swap $P_1$ and $P_2$.      * ",
      "description_type": "Markdown"
    },
    "platform": "AtCoder",
    "limit": {
      "time_limit": 2000,
      "memory_limit": 262144
    },
    "difficulty": "None",
    "is_remote": true,
    "is_sync": true,
    "sync_url": null,
    "sign": "arc110_c"
  },
  "statements": [
    {
      "statement_type": "Markdown",
      "content": "We have a permutation $P = P_1, P_2, \\ldots, P_N$ of $1, 2, \\ldots, N$.\nYou have to do the following $N - 1$ operations on $P$, **each exactly once**, in some order:\n\n*   Swap $P_1$ and $P_2$.\n    \n* ...",
      "is_translate": false,
      "language": "English"
    }
  ]
}

Full JSON Raw Segments