In this challenge your task was to multiply two strings, this naturally introduces a way to take the square root of a string.
How does it work?
Given a string (for example
pub) the first thing you need to do, is to determine the ASCII code for each character:
"pub" -> [112, 117, 98]
Next you map these codes to the range
[0..94] by subtracting
32 of each value:
[112, 117, 98] -> [80, 85, 66]
Now you need to find for each value its root modulo
40*40 % 95 = 80, you could also pick
[80, 85, 66] -> [40, 35, 16]
And finally you'll map it back to the range
[32..126] and convert it back to a string:
[40, 35, 16] -> [72, 67, 48] -> "HC0"
"HC0" ⊗ "HC0" = "pub" as you can verify with a solution from the other challenge here.
The ones familiar with modular arithmetic probably noticed that the square root modulo
95 does not always exist, for example there's no root for
2. In such a case the square root of a string is not defined and your program/function may crash, loop indefinetly etc.
For your convenience, here's the list of chars that have a square root (the first one is a space):
- You will write a program/function that takes a string (or list of chars) as an argument and returns any square root if it exists
- You may assume that the input always has a square root
- The input may consist of an empty string
- The input will be in the printable range (
- The output is either printed to the console or you return a string if the square root exists
- In case the square root doesn't exist, the behavior of your program/function is left undefined
- If you choose to print the root to the console trailing newlines or whitespaces are fine
Note that these are not necessarily the only solutions:
'' -> '' 'pub' -> 'HC0' 'pull!' -> 'HC33!' 'M>>M' -> '>MM>' '49' -> '4%' '64' -> undefined 'Hello, World!' -> undefined