Official Analysis (Java)

Explanation

We generate a larger grid repeating each character from the small grid both horizontally and vertically, so that every character becomes a block of identical characters in the final output.

To do this, we can first repeat each of the $N$ characters per row $K$ consecutive times, and repeat each of these expanded rows in the grid $K$ consecutive times as well.

Video Solution

By Jeffrey Meng

Implementation

Time Complexity: $\mathcal{O}(MN \cdot K^2)$

Copy
with open("cowsignal.in") as read:
	height, width, scale = map(int, read.readline().split())
	signal = [read.readline() for _ in range(height)]

with open("cowsignal.out", "w") as written:
	for i in range(scale * height):
		for j in range(scale * width):
			print(signal[i // scale][j // scale], end="", file=written)

		print(file=written)