摘要：
链接：https://codeforces.com/problemset/problem/1215/D Monocarp and Bicarp live in Berland, where every bus ticket consists of nn digits (nn is an even n 阅读全文
摘要：
链接：https://codeforces.com/problemset/problem/1215/C Swap Letters （2 seconds） Monocarp has got two strings ss and tt having equal length. Both strings 阅读全文