Yandex.Algorithm Open 2011: Qualification 1
D
Polycarp's Picture Gallery
Codeforces
2100
原题
← CE →
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Polycarp loves not only to take pictures, but also to show his photos to friends. On his personal website he has recently installed a widget that can display $*n*$ photos with the scroll option. At each moment of time the widget displays exactly one photograph with the option showing the previous/next one. From the first photo, you can switch to the second one or to the $*n*$-th one, from the second photo you can switch to the third one or to the first one, etc. Thus, navigation is performed in a cycle.

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Polycarp's collection consists of $*m*$ photo albums, the $*i*$-th album contains $*a*_{*i*}$ photos. Polycarp wants to choose $*n*$ photos and put them on a new widget. To make watching the photos interesting to the visitors, he is going to post pictures so that no two photos from one album were neighboring (each photo will have exactly two neighbors, the first photo's neighbors are the second and the $*n*$-th one).

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Help Polycarp compile a photo gallery. Select $*n*$ photos from his collection and put them in such order that no two photos from one album went one after the other.

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Input

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The first line contains two integers $*n*$ and $*m*$ ($3 ≤ *n* ≤ 1000$, $1 ≤ *m* ≤ 40$), where $*n*$ is the number of photos on the widget, and $*m*$ is the number of albums. The second line contains $*m*$ integers $*a*_{1}, *a*_{2}, ..., *a*_{*m*}$ ($1 ≤ *a*_{*i*} ≤ 1000$), where $*a*_{*i*}$ is the number of photos in the $*i*$-th album.

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Output

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Print the single number -1 if there is no solution. Otherwise, print $*n*$ numbers $*t*_{1}, *t*_{2}, ..., *t*_{*n*}$, where $*t*_{*i*}$ represents the number of the album of the $*i*$-th picture in the widget. The albums are numbered from 1 in the order of their appearance in the input. If there are several solutions, print any of them.

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样例

Input #1
4 3
1 3 5
Output #1
3 1 3 2
InputCopy OutputCopy
Input #2
10 2
5 5
Output #2
2 1 2 1 2 1 2 1 2 1
InputCopy OutputCopy
Input #3
10 3
1 10 3
Output #3
-1
InputCopy OutputCopy
题目信息
题号
81D
时间限制
2 s
内存限制
256 MB
标签
构造
贪心

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。