大学的每个专业都要编制教学计划。假设任何专业都有固定的学习年限，每学年含两学期，每学期的时间长度和学分上限都相等。每个专业开设的课程都是确定的，而且课程的开设时间的安排必须满足先修关系。每个课程的先修关系都是确定的，可以有任意多门，也可以没有。每一门课程恰好一个学期。试在这样的情况下设置一个教学计划编制程序。

基本要求：

（1）：输入参数：学期总数，一学期的学分上限，每门课的课程号，学分，直接先修关系的课程号。

（2）：课程号尽可能的集中在前几个学期中。

（3）：若无解，则报告错误信息；否则见教学计划输入到指定的文件中。计划的表格格式自行设计。

-University of each professional should prepare teaching plans. The assumption that any professional have fixed the length of each school year with two semesters each semester and the length of time equal to the credit limit are. Every professional courses are opened to determine, and the creation of curriculum time arrangements must meet pre relations. Each course is the pre-established relationship, can have any more doors, there will be no. Each course just one semester. Tests in the circumstances set up a teaching program procedures. Basic requirements : (1) : input parameters : total semester, a semester's credit ceiling for each class courses, credits, the direct prevocational courses,. (2) : No. possible courses focus had previous semester. (3) : If there are no solutions, the re