题目描述Let $f(n)$ be a sum of digits for positive integer $n$. If $f(n)$ is one-digit number then it is a digital root for $n$ and otherwise digital root of $n$ is equal to digital root of $f(n)$. For ex

准备工作镜像下载 && 启动盘制作镜像文件可以直接从官方网站上下载。 下载完成后，Windows 用户可以用 Ultraiso 制作启动盘，Linux 用户可以用 dd 制作启动盘，具体如下： 1# dd if=*.iso of=/dev/sd* 其中if表示输入文件，of表示输出文件，/dev/sd*表示 U 盘。具体参数要根据实际情况确定。 开始安装 && 分

题目概述Nearly prime number is an integer positive number for which it is possible to find such primes $P_1$ and $P_2$ that given number is equal to $P_1 \times P_2$. There is given a sequence on $N$ inte

题目描述The mission of space explorers found on planet M the vast dungeon. One of the dungeon halls is fill with the bright spheres. The explorers find out that the light rays reflect from the surface of

题目描述There is an equation $ax+by+c=0$. Given $a,b,c,x_1,x_2,y_1,y_2$ you must determine, how many integer roots of this equation are satisfy to the following conditions: $x_1 \le x \le x_2, \ y_1

题目描述In the city of Dingilville the traffic is arranged in an unusual way. There are junctions and roads connecting the junctions. There is at most one road between any two different junctions. There i

题目描述Dominoes - game played with small, rectangular blocks of wood or other material, each identified by a number of dots, or pips, on its face. The blocks usually are called bones, dominoes, or pieces

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题目描述Mojtaba and Arpa are playing a game. They have a list of $n$ numbers in the game. In a player’s turn, he chooses a number $p^k$ (where $p$ is a prime number and $k$ is a positive integer) such tha

题目描述Arpa has found a list containing $n$ numbers. He calls a list bad if and only if it is not empty and gcd of numbers in the list is $1$. Arpa can perform two types of operations: Choose a number a