十年换你一句好久不见

摘要： D. Make a Permutation! Ivan has an array consisting of n elements. Each of the elements is an integer from 1 to n. Recently Ivan learned about permuta 阅读全文

摘要： B. Train Seats Reservation You are given a list of train stations, say from the station 1 to the station 100. The passengers can order several tickets 阅读全文

摘要： C. Mahmoud and Ehab and the xor Mahmoud and Ehab are on the third stage of their adventures now. As you know, Dr. Evil likes sets. This time he won't 阅读全文

摘要： Mahmoud and Ehab and the bipartiteness Mahmoud and Ehab continue their adventures! As everybody in the evil land knows, Dr. Evil likes bipartite graph 阅读全文

摘要： Bob has a not even coin, every time he tosses the coin, the probability that the coin's front face up is qp(qp≤12)\frac{q}{p}(\frac{q}{p} \le \frac{1} 阅读全文

摘要： D - joisino's travel Problem Statement There are N towns in the State of Atcoder, connected by M bidirectional roads. The i-th road connects Town Ai a 阅读全文

摘要： 日天学长向妹子表白了，妹子说：“日天你那么聪明，回答我一个问题就答应你。你告诉我，L位K进制数有多少个？”日天表示这个问题太简单了，要求提高难度。妹子想了想说：“那么我增加一个要求，一个满足要求的L位K进制数，任意两位相邻的数字相减的绝对值不能等于一，你能告诉我，有多少个满足条件的L位K进制数么？” 阅读全文

摘要： G. Bathroom terminal Smith wakes up at the side of a dirty, disused bathroom, his ankle chained to pipes. Next to him is tape-player with a hand-writt 阅读全文

摘要： A. Arpa and a research in Mexican wave Arpa is researching the Mexican wave. There are n spectators in the stadium, labeled from 1 to n. They start th 阅读全文

摘要： C - 4-adjacent Time limit : 2sec / Memory limit : 256MB Score : 400 points Problem Statement We have a sequence of length N, a=(a1,a2,…,aN). Each ai i 阅读全文