摘要：
CRB has a tree, whose vertices are labeled by 1, 2, …, N. They are connected by N – 1 edges. Each edge has a weight. For any two vertices u and v(poss 阅读全文
摘要：
Problem Description CRB has two strings s and t. In each step, CRB can select arbitrary character c of s and insert any character d (d ≠ c) just after 阅读全文