I'm attempting this code challenge.
Here's my code modified to handle one simple example test case:
string = "bcdefghij"
l = string.size
result = []
permutations = string.split('').permutation.to_a
string.sizel.times do
permutations.each {|p| result << p.sort.join}
permutations.map! {|p| p[1..-1]}
end
puts result.uniq.sort
It produces the correct result but it's way too slow. I've played around with benchmarking and it looks like the slowest part of the code is this line:
permutations.each {|p| result << p.sort.join}
Can I speed this code up somehow? Or am I thinking about the original problem all wrong?
RESULT
Thanks to Nat's answer below I came up with this:
string = "bcdefghij".split('')
l = string.length
result = []
(1..(string.size)l).each {|i| result += string.combination(i).to_a}
puts result.map{|r| r.join}.sort
Benchmarks
Before: 6.480000 0.310000 6.790000 ( 6.794669)
After: 0.000000 0.000000 0.000000 ( 0.003087)