摘要：
Anadi has a set of dominoes. Every domino has two parts, and each part contains some dots. For every aa and bb such that 1≤a≤b≤61≤a≤b≤6, there is exac 阅读全文
摘要：
The only difference between the easy and the hard versions is the maximum value of kk. You are given an infinite sequence of form "112123123412345……" 阅读全文
摘要：
Dawid has four bags of candies. The ii-th of them contains aiai candies. Also, Dawid has two friends. He wants to give each bag to one of his two frie 阅读全文
摘要：
Ania has a large integer SS. Its decimal representation has length nn and doesn't contain any leading zeroes. Ania is allowed to change at most kk dig 阅读全文