Question

I am trying to take a string, between length 1 and 10, and output all possible ways of breaking up the string into consecutive substrings that are of sizes 1, 2, or 3. For example:

Input: 123456

Slice the integer into individual characters, then proceed through to find combinations.
The code would return all of the following arrays.

    [1, 2, 3, 4, 5, 6]  
    [12, 3, 4, 5, 6]  
    [1, 23, 4, 5, 6]  
    [1, 2, 34, 5, 6]  
    [1, 2, 3, 45, 6]  
    [1, 2, 3, 4, 56]  
    [12, 34, 5, 6]  
    [12, 3, 45, 6]  
    [12, 3, 4, 56]  
    [1, 23, 45, 6]  
    [1, 2, 34, 56]  
    [1, 23, 4, 56]  
    [12, 34, 56]  
    [123, 4, 5, 6]  
    [1, 234, 5, 6]  
    [1, 2, 345, 6]  
    [1, 2, 3, 456]  
    [123, 456]  
    [1, 23, 456]  
    [1, 234, 56]  
    [12, 345, 6]  
    [12, 3, 456]  
    [123, 4, 56]  
    [123, 45, 6]

I’m trying to do this in ruby. Thanks!

Answer 1

Here’s a working function. May be not optimal as I didn’t spend much time on it.

str = "1234567890"

def f(s, n)
    return [[]] if s.empty?

    (1..[n, s.length].min).map{|c| f(s[c..-1], n).map{|a| [s[0, c]] + a}}.inject(&:+)
end

puts f(str, 3).collect{|l| l * "\t"}

EDIT: Made it a bit shorter and the length is now passed as second parameter to function for flexibility.