摘要：
You are given a non-empty string s=s1s2…sns=s1s2…sn, which consists only of lowercase Latin letters. Polycarp does not like a string if it contains at 阅读全文
摘要：
After the fourth season Sherlock and Moriary have realized the whole foolishness of the battle between them and decided to continue their competitions 阅读全文
摘要：
Recall that string aa is a subsequence of a string bb if aa can be obtained from bb by deletion of several (possibly zero or all) characters. For exam 阅读全文