TNVFC1L - Letters
We build the infinite sequence of uppercase letters (A-Z) which starts with single-letter strings (A, B, ..., Z), continues with two-letter strings (AA, AB, ..., AZ, BA, BB, ..., BZ, ..., ZZ), then three letter strings and so on. The same-length strings are ordered lexicographically. We are interested in finding which letter sits at a given index in the sequence.
The letter index, ranging between 0 and 2*10^9.
The letter at the specified index.
0 25 50 100 250 500 1000
A Z A B E J S
Alternatively a judge can be changed to binary.
This should be put into "partial" section, because it doesn't use binary judge.