According to rules of the Berland fashion, a jacket should be fastened by all the buttons except only one, but not necessarily it should be the last one. Also i...

Limak is going to participate in a contest on the last day of the 2016. The contest will start at 20:00 and will last four hours, exactly until midnight. There ...

给定两个字符串string1和string2，判断string2是否为string1的子串。

有n个小朋友，每个小朋友手里有一些糖块，现在这些小朋友排成一排，编号是由1到n。现在给出m个数，能不能唯一的确定一对值l和r(l <= r)，使得这m个数刚好是第l个小朋友到第r个小朋友手里的糖块数？...

N wizards are attending a meeting. Everyone has his own magic wand. N magic wands was put in a line, numbered from 1 to n(Wand_i owned by wizard_i). After the m...

There are n single boys and m single girls. Each of them may love none, one or several of other people unrequitedly and one-sidedly. For the coming q days, each...

The modular modular multiplicative inverse of an integer a modulo m is an integer xsuch that a-1≡x (mod m). This is equivalent to ax≡1 (mod m).

New game是在一个M*M的特殊棋盘（棋盘的第i行都标上了数字i）上进行的新式游戏。给定一个数字N，要求选手把一个棋子从左上角（1，1）移到右下角（M，M），移动时只能往右或往下。要求移动后经过的数字和为N，且拐弯的次数最少。 如果对给出...

话说这个世界上有各种各样的兔子和乌龟，但是 研究发现，所有的兔子和乌龟都有一个共同的特点——喜欢赛跑。于是世界上各个角落都不断在发生着乌龟和兔子的比赛，小华对此很感兴趣，于是决定研究不同兔 子和乌龟的赛跑。他发...

观察数字：12321，123321 都有一个共同的特征，无论从左到右读还是从右向左读，都是相同的。这样的数字叫做：回文数字。