1.全排列 https://blog.csdn.net/qq_32631105/article/details/88741382 2.子集 https://blog.csdn.net/qq_32631105/article/details/88748775 3.素数环 https://blog.csdn.net/qq_32631105/article/details/88743415 4.n皇后 https://blog.csdn.net/qq_32631105/article/details/88742533