在开发中如果有接触到加密，就一定遇到过MD5、DES、Triple DES、AES、RSA等加密方式（这些都叫加密算法）；在深入了解加密领域的知识时，除了有加密算法外；还有加密模式（CBC、ECB、CTR、OCF、CFB等），填充模式（NoPadding、PKCS5Paddi...

多个线程同时被阻塞，它们中的一个或者全部都在等待某个资源被释放。由于线程被无限期地阻塞，因此程序不可能正常终止。

There are N robots standing on the ground (Don't know why. Don't know how).

Your task is to divide a number of persons into two teams, in such a way, that: everyone belongs to one of the teams; every team has at least one member; ...

给你一个图，n个点m条边，求走遍所有边，至少经过几次点，及输出依次经过的点。n and m (2 ≤ n ≤ 10^5, 1 ≤ m ≤ 2·10^5)

给你一串数，a1...an,从左到右每次让一个数减小c，如果这个数小于c，那就减为0。第n个数减小后，又从第一个开始从左到右。如果这次某个数减小到0，那就改变方向，如果遇到已经是0的，就跳过。且总共最多减少n+5次，求最后变为0的数是...

Give a time.(hh:mm:ss)，you should answer the angle between any two of the minute.hour.second hand Notice that the answer must be not more 180 and not less than...

soda has a set $S$ with $n$ integers ${1, 2, dots, n}$. A set is called key set if the sum of integers in the set is an even number. He wants to know how man...

Theater stage is a rectangular field of size n × m. The director gave you the stage's plan which actors will follow. For each cell it is stated in the plan if t...

海洋包围的小岛，岛内的有湖，'.'代表水，'*'代表陆地，给出的n*m的地图里至少有k个湖，求填掉面积尽量少的水，使得湖的数量正好为k。...