Hi, I'm a korean. I'm not good yet English. So, I don't understand a sentence.
This mapping is one-to-one and onto, which means that the same input letter always gets replaced with the same output letter, and different input letters always get replaced with different output letters.
This sentence is A.Problem in google code jem Qualification Round 2012. https://code.google.com/codejam/contest/1460488/dashboard
I understand "one-to-one", it same "1:1".
but, "onto" don't understand to mean.
in English-Korean dictionary, To mean "onto" is same "across".
ex) When my name was called, he looked across
but, It isn't right mean. So, I asked help you.
And, I find To mean "onto", Do "onto" same The link?http://en.wikipedia.org/wiki/Surjective_function