201492: [AtCoder]ARC149 C - Avoid Prime Sum

Memory Limit:1024 MB Time Limit:2 S
Judge Style:Text Compare Creator:
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Description

Score : $500$ points

Problem Statement

You are given a positive integer $N$.

Fill each square of a grid with $N$ rows and $N$ columns by writing a positive integer not greater than $N^2$ so that all of the following conditions are satisfied.

  • Two positive integers written in horizontally or vertically adjacent squares never sum to a prime number.
  • Every positive integer not greater than $N^2$ is written in one of the squares.

Under the Constraints of this problem, it can be proved that such a way to fill the grid always exists.

Constraints

  • $3\leq N\leq 1000$

Input

The input is given from Standard Input in the following format:

$N$

Output

Print a way to fill the grid under the conditions in the following format, where $A_{ij}$ is the positive integer at the $i$-th row and $j$-th column:

$A_{11}$ $\ldots$ $A_{1N}$
$\vdots$
$A_{N1}$ $\ldots$ $A_{NN}$

If there are multiple ways to fill the grid under the conditions, any of them will be accepted.


Sample Input 1

4

Sample Output 1

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

In this grid, every positive integer from $1$ through $16$ is written once. Additionally, among the sums of two positive integers written in horizontally or vertically adjacent squares are $15+11=26$, $11+16=27$, and $15+13=28$, none of which is a prime number.

Input

题意翻译

构造一种方案,用 $1\sim n^2$ 填充一个 $n\times n$ 的方格,使任意两个相邻的数的和不为质数。

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