Codeforces Round 770 (Div. 2)
C
OKEA
Codeforces
1000
原题
← BD →
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People worry that computers will get too smart and take over the world, but the real problem is that they're too stupid and they've already taken over the world.— Pedro Domingos

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You work for a well-known department store that uses leading technologies and employs mechanistic work — that is, robots!

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The department you work in sells $n \cdot k$ items. The first item costs $1$ dollar, the second item costs $2$ dollars, and so on: $i$-th item costs $i$ dollars. The items are situated on shelves. The items form a rectangular grid: there are $n$ shelves in total, and each shelf contains exactly $k$ items. We will denote by $a_{i,j}$ the price of $j$-th item (counting from the left) on the $i$-th shelf, $1 \le i \le n, 1 \le j \le k$.

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Occasionally robots get curious and ponder on the following question: what is the mean price (arithmetic average) of items $a_{i,l}, a_{i,l+1}, \ldots, a_{i,r}$ for some shelf $i$ and indices $l \le r$? Unfortunately, the old robots can only work with whole numbers. If the mean price turns out not to be an integer, they break down.

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You care about robots' welfare. You want to arrange the items in such a way that the robots cannot theoretically break. Formally, you want to choose such a two-dimensional array $a$ that:

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  • Every number from $1$ to $n \cdot k$ (inclusively) occurs exactly once.
  • For each $i, l, r$, the mean price of items from $l$ to $r$ on $i$-th shelf is an integer.
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Find out if such an arrangement is possible, and if it is, give any example of such arrangement.

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Input

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The first line contains a single integer $t$ ($1 \le t \le 500$) — the number of test cases.

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The first and only line of each test case contains two integers $n$ and $k$ ($1 \le n, k \le 500$) — the number of shelves and length of each shelf, respectively.

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It is guaranteed that the sum $n$ over all test cases does not exceed $500$ and the sum $k$ over all test cases does not exceed $500$.

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Output

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Print the answer for each test case.

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If such an arrangement exists, print "YES" on a single line. After that, print any example on $n$ lines of $k$ numbers each, one line per shelf. Each number from $1$ to $n \cdot k$ must occur exactly once in the output.

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If no good arrangement exists, print a single word "NO" on its own line.

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样例

Input #1
4
1 1
2 2
3 3
3 1
Output #1
YES
1
YES
1 3
2 4
NO
YES
1
2
3
InputCopy OutputCopy
题目信息
题号
1634C
时间限制
1 s
内存限制
256 MB
标签
构造

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。