摘要:
For the given integer nn (n>2n>2 ) let's write down all the strings of length nn which contain n−2n−2 letters 'a' and two letters 'b' in lexicographic 阅读全文
摘要:
You are given two positive integers aa and bb. In one move you can increase aa by 11 (replace aa with a+1a+1). Your task is to find the minimum number 阅读全文