Problem Description Give a number n, find the minimum x(x>0) that satisfies 2^x mod n = 1.

Problem Description A weird clock marked from 0 to 59 has only a minute hand. It won’t move until a special coin is thrown into its box. There are different k...

Problem Description Starting from point (0,0) on a plane, we have written all non-negative integers 0, 1, 2,… as shown in the figure. For example, 1, 2, and 3...

Problem Description From the article Number Theory in the 1994 Microsoft Encarta: “If a, b, c are integers such that a = bc, a is called a multiple of b or of...

Problem Description 一个正整数，如果从左向右读（称之为正序数）和从右向左读（称之为倒序数）是一样的，这样的数就叫回文数。任取一个正整数，如果不是回文数，将该数与他的倒序数相加，若其和不是回文数，则重复上述步骤，一直到获得...

Problem Description 数论中有许多猜想尚未解决，其中有一个被称为“角谷猜想”的问题，该问题在五、六十年代的美国多个著名高校中曾风行一时，这个问题是这样描述的：任何一个大于一的自然数，如果是奇数，则乘以三再加一；如果...

Problem Description Welcome to 2006’4 computer college programming contest!

Problem Description 今天的上机考试虽然有实时的Ranklist，但上面的排名只是根据完成的题数排序，没有考虑 每题的分值，所以并不是最后的排名。给定录取分数线，请你写程序找出最后通过分数线的 考生，并将他们的成绩按降...

Problem Description 每学期的期末，大家都会忙于计算自己的平均成绩，这个成绩对于评奖学金是直接有关的。国外大学都是计算GPA(grade point average) 又称GPR(grade point ratio)，即成绩点数与学分的加权平均值来代表一...

Problem Description Find and list all four-digit numbers in decimal notation that have the property that the sum of its four digits equals the sum of its digi...