Codeforces Round 428 (Div. 2)
B
Game of the Rows
Codeforces
1900
原题
← AC →
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Daenerys Targaryen has an army consisting of $*k*$ groups of soldiers, the $*i*$-th group contains $*a*_{*i*}$ soldiers. She wants to bring her army to the other side of the sea to get the Iron Throne. She has recently bought an airplane to carry her army through the sea. The airplane has $*n*$ rows, each of them has $8$ seats. We call two seats neighbor, if they are in the same row and in seats ${1, 2}$, ${3, 4}$, ${4, 5}$, ${5, 6}$ or ${7, 8}$.

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image A row in the airplane

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Daenerys Targaryen wants to place her army in the plane so that there are no two soldiers from different groups sitting on neighboring seats.

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Your task is to determine if there is a possible arranging of her army in the airplane such that the condition above is satisfied.

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Input

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The first line contains two integers $*n*$ and $*k*$ ($1 ≤ *n* ≤ 10000$, $1 ≤ *k* ≤ 100$) — the number of rows and the number of groups of soldiers, respectively.

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The second line contains $*k*$ integers $*a*_{1}, *a*_{2}, *a*_{3}, ..., *a*_{*k*}$ ($1 ≤ *a*_{*i*} ≤ 10000$), where $*a*_{*i*}$ denotes the number of soldiers in the $*i*$-th group.

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It is guaranteed that $*a*_{1} + *a*_{2} + ... + *a*_{*k*} ≤ 8·*n*$.

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Output

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If we can place the soldiers in the airplane print "YES" (without quotes). Otherwise print "NO" (without quotes).

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You can choose the case (lower or upper) for each letter arbitrary.

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Note

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In the first sample, Daenerys can place the soldiers like in the figure below:

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image

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In the second sample, there is no way to place the soldiers in the plane since the second group soldier will always have a seat neighboring to someone from the first group.

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In the third example Daenerys can place the first group on seats $(1, 2, 7, 8)$, and the second group an all the remaining seats.

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In the fourth example she can place the first two groups on seats $(1, 2)$ and $(7, 8)$, the third group on seats $(3)$, and the fourth group on seats $(5, 6)$.

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样例

Input #1
2 2
5 8
Output #1
YES
InputCopy OutputCopy
Input #2
1 2
7 1
Output #2
NO
InputCopy OutputCopy
Input #3
1 2
4 4
Output #3
YES
InputCopy OutputCopy
Input #4
1 4
2 2 1 2
Output #4
YES
InputCopy OutputCopy
题目信息
题号
839B
时间限制
1 s
内存限制
256 MB
标签
暴力
贪心
模拟

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。