Codeforces Round 359 (Div. 2)
B
Little Robber Girl's Zoo
Codeforces
1100
原题
← AC →
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Little Robber Girl likes to scare animals in her zoo for fun. She decided to arrange the animals in a row in the order of non-decreasing height. However, the animals were so scared that they couldn't stay in the right places.

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The robber girl was angry at first, but then she decided to arrange the animals herself. She repeatedly names numbers $*l*$ and $*r*$ such that $*r* - *l* + 1$ is even. After that animals that occupy positions between $*l*$ and $*r*$ inclusively are rearranged as follows: the animal at position $*l*$ swaps places with the animal at position $*l* + 1$, the animal $*l* + 2$ swaps with the animal $*l* + 3$, ..., finally, the animal at position $*r* - 1$ swaps with the animal $*r*$.

翻译中…

Help the robber girl to arrange the animals in the order of non-decreasing height. You should name at most $20 000$ segments, since otherwise the robber girl will become bored and will start scaring the animals again.

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Input

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The first line contains a single integer $*n*$ ($1 ≤ *n* ≤ 100$) — number of animals in the robber girl's zoo.

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The second line contains $*n*$ space-separated integers $*a*_{1}, *a*_{2}, ..., *a*_{*n*}$ ($1 ≤ *a*_{*i*} ≤ 10^{9}$), where $*a*_{*i*}$ is the height of the animal occupying the $*i*$-th place.

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Output

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Print the sequence of operations that will rearrange the animals by non-decreasing height.

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The output should contain several lines, $*i*$-th of the lines should contain two space-separated integers $*l*_{*i*}$ and $*r*_{*i*}$ ($1 ≤ *l*_{*i*} < *r*_{*i*} ≤ *n*$) — descriptions of segments the robber girl should name. The segments should be described in the order the operations are performed.

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The number of operations should not exceed $20 000$.

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If the animals are arranged correctly from the start, you are allowed to output nothing.

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Note

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Note that you don't have to minimize the number of operations. Any solution that performs at most $20 000$ operations is allowed.

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样例

Input #1
4
2 1 4 3
Output #1
1 4
InputCopy OutputCopy
Input #2
7
36 28 57 39 66 69 68
Output #2
1 4
6 7
InputCopy OutputCopy
Input #3
5
1 2 1 2 1
Output #3
2 5
3 4
1 4
1 4
InputCopy OutputCopy
题目信息
题号
686B
时间限制
2 s
内存限制
256 MB
标签
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