Codeforces Round 877 (Div. 2)
C
No Prime Differences
Codeforces
1400
原题
← BD →
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You are given integers $n$ and $m$. Fill an $n$ by $m$ grid with the integers $1$ through $n\cdot m$, in such a way that for any two adjacent cells in the grid, the absolute difference of the values in those cells is not a prime number. Two cells in the grid are considered adjacent if they share a side.

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image

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It can be shown that under the given constraints, there is always a solution.

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Input

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The first line of the input contains a single integer $t$ ($1 \le t \le 1000$) — the number of test cases. The description of the test cases follows.

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The first and only line of each test case contains two integers $n$ and $m$ ($4 \le n, m \le 1000$) — the dimensions of the grid.

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It is guaranteed that the sum of $n\cdot m$ over all test cases does not exceed $10^6$.

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Output

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For each test case, output $n$ lines of $m$ integers each, representing the final grid. Every number from $1$ to $n\cdot m$ should appear exactly once in the grid.

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The extra spaces and blank lines in the sample output below are only present to make the output easier to read, and are not required.

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If there are multiple solutions, print any of them.

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Note

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The first sample case corresponds to the picture above. The only absolute differences between adjacent elements in this grid are $1$, $4$, $6$, $8$, and $9$, none of which are prime.

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样例

Input #1
3
4 4
5 7
6 4
Output #1
16  7  1  9
12  8  2  3
13  4 10 11
14  5  6 15

29 23 17  9  5  6  2
33 27 21 15 11  7  1
32 31 25 19 20 16 10
26 30 24 18 14  8  4
35 34 28 22 13 12  3

 2  3  7 11
 8  9  1 10
17 13  5  4
18 14  6 12
19 23 15 21
20 24 16 22
InputCopy OutputCopy
题目信息
题号
1838C
时间限制
2 s
内存限制
256 MB
标签
构造
数学
数论

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。