CARDS Time Limit: 1000MS Memory Limit: 10000K Total Submissions: 1448 Accepted: 773 Description Alice and Bob have a set of N cards labelled with numbers 1 ... N (so that no two cards have the same label) and a shuffle machine. We assume that N i…
18.2 Write a method to shuffle a deck of cards. It must be a perfect shuffle—in other words, each of the 52! permutations of the deck has to be equally likely. Assume that you are given a random number generator which is perfect. 这道题让我们实现一个洗牌的算法,实际上洗…
题意:给你一个置换P,问是否存在一个置换M,使M^2=P 思路:资料参考 <置换群快速幂运算研究与探讨> https://wenku.baidu.com/view/0bff6b1c6bd97f192279e9fb.html 结论一: 一个长度为 l 的循环 T,l 是 k 的倍数,则 T^k 是 k 个循环的乘积,每个循环分别是循环 T 中下标 i mod k=0,1,2- 的元素按顺序的连接. 结论二:一个长度为 l 的循环 T,gcd(l,k)=1,则 T^k 是一个循环,与循环 T 不一…
Raising Modulo Numbers Time Limit: 1000MS Memory Limit: 30000K Total Submissions: 9745 Accepted: 5921 Description People are different. Some secretly read magazines full of interesting girls' pictures, others create an A-bomb in their cellar, oth…
链接:http://poj.org/problem?id=1026 Cipher Time Limit: 1000MS Memory Limit: 10000K Total Submissions: 21436 Accepted: 5891 Description Bob and Alice started to use a brand-new encoding scheme. Surprisingly it is not a Public Key Cryptosystem, but t…
Invoker Problem Description On of Vance's favourite hero is Invoker, Kael. As many people knows Kael can control the elements and combine them to invoke a powerful skill. Vance like Kael very much so he changes the map to make Kael more powerful. In…
