摘要：
题目描述 You are given a string S consisting of lowercase English letters. Another string T is initially empty. Determine whether it is possible to obtain 阅读全文
摘要：
题目描述 There are N towns located in a line, conveniently numbered 1 through N. Takahashi the merchant is going on a travel from town 1 to town N, buying 阅读全文