Your code looks OK, you might make it faster by checking the words have the same length before the actual sort:
while !STDIN.gets.chomp.empty?
first_word, second_word = $_.downcase.split
if first_word.length == second_word.length &&
first_word.chars.sort == second_word.chars.sort
puts "YES"
else
puts "NO"
end
end
1
solved slow algorithm contest