10593: ABC357 —— C - Sierpinski carpet
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Description
For a non-negative integer $K$, we define a level-$K$ carpet as follows:
- A level-$0$ carpet is a $1 \times 1$ grid consisting of a single black cell.
- For $K > 0$, a level-$K$ carpet is a $3^K \times 3^K$ grid. When this grid is divided into nine $3^{K-1} \times 3^{K-1}$ blocks:
- The central block consists entirely of white cells.
- The other eight blocks are level-$(K-1)$ carpets.
You are given a non-negative integer $N$.
Print a level-$N$ carpet according to the specified format.
- A level-$0$ carpet is a $1 \times 1$ grid consisting of a single black cell.
- For $K > 0$, a level-$K$ carpet is a $3^K \times 3^K$ grid. When this grid is divided into nine $3^{K-1} \times 3^{K-1}$ blocks:
- The central block consists entirely of white cells.
- The other eight blocks are level-$(K-1)$ carpets.
You are given a non-negative integer $N$.
Print a level-$N$ carpet according to the specified format.
Input
The input is given from Standard Input in the following format:
```
$N$
```
```
$N$
```
Output
Print $3^N$ lines.
The $i$-th line ($1 \leq i \leq 3^N$) should contain a string $S_i$ of length $3^N$ consisting of `.` and `#`.
The $j$-th character of $S_i$ ($1 \leq j \leq 3^N$) should be `#` if the cell at the $i$\-th row from the top and $j$\-th column from the left of a level-$N$ carpet is black, and `.` if it is white.
The $i$-th line ($1 \leq i \leq 3^N$) should contain a string $S_i$ of length $3^N$ consisting of `.` and `#`.
The $j$-th character of $S_i$ ($1 \leq j \leq 3^N$) should be `#` if the cell at the $i$\-th row from the top and $j$\-th column from the left of a level-$N$ carpet is black, and `.` if it is white.
Constraints
- $0 \leq N \leq 6$
- $N$ is an integer.
- $N$ is an integer.
Sample 1 Input
1
Sample 1 Output
###
#.#
###
A level-$1$ carpet is a $3 \times 3$ grid as follows:
When output according to the specified format, it looks like the sample output.
When output according to the specified format, it looks like the sample output.
Sample 2 Input
2
Sample 2 Output
#########
#.##.##.#
#########
###...###
#.#...#.#
###...###
#########
#.##.##.#
#########
A level-$2$ carpet is a $9 \times 9$ grid.