Dec 01 Programmers Challenge
Volume Number: 17 (2001)
Issue Number: 12
Column Tag: Programmer's Challenge
by Bob Boonstra, Westford, MA
If you have children in school, you are familiar with parent-teacher conferences. Little Johnny isn’t doing so well in French, or Algebra, or perhaps Advanced Calculus if your school has a gifted and talented program. Or Sally is doing very well in Subatomic Physics, and you’d like to hear her teachers tell you so.
I was reminded recently of a Challenge suggested by Ernst Munter to write code that would help schools schedule these conferences. Your Challenge this month is to arrange a set of parent-teacher conferences that maximize the parents’ satisfaction and minimize the amount of time wasted by both parents and teachers in between conferences.
You will be given three data sets to work with for each test case. The first, in a file childrenNN.txt (where NN is a number from 01 to the number of test cases), will have one line for each child in the school, containing the child’s name followed by the names of one or two parents. No child will appear on more than one line, and there will be no duplicate names of children. A sample would be the following:
Johnny Smith, Donald Smith, Marilyn Waters-Smith
Sally Jones,Samantha Jones
The second data set, in a file named teachersNN.txt, maps children to their teachers. Each line contains the name of a child, followed by the name of one of his/her teachers, followed by a number from 0 to 9 indicating the strength of the parents’ desire to talk with that teacher. A value of 0 indicates no conference is desired, up to a value of 9 indicating the strongest desire for a conference. Example lines from this file might be:
Johnny Smith, Richard Darwin, 3
Johnny Smith, Rene Descartes, 9
Johnny Smith, Edgar Allen Poe, 0
Sally Jones, Rene Descartes, 5
Sally Jones, Albert Einstein, 9
The final data set, in a file named schedulesNN.txt, identifies which parents are available at which times. The first line in this file contains the number N of conference periods available for scheduling. All teachers can be available for any or all of the periods from 1..N. Subsequent lines contain the names of parents, along with the first and the last conference period for which they will be available. Parents will be available for any period between their first and last available periods, inclusive. Each parent whose name appears in the children.txt file will appear on one line in the schedules.txt file. Example lines from this file might be:
Donald Smith, 1,9
Samantha Jones, 4,9
Finally, the number of test cases is provided in a file input.txt, with a single line containing the number of test cases:
Your code needs to produce output that provides the matching of parents to teachers. The output (conferencesNN.txt) should contain one line for each conference, with the name of the teacher first, the name of the parent second, and the conference period third. No parent or teacher can be in more than one conference during a given period. Both parents of a given child can participate in a conference with a teacher if they are both available during that period (two lines would be output in such a case). One line in such a file might be:
Richard Darwin,Marilyn Waters-Smith,5
Finally, your solution needs to produce a log file (log.txt) that contains, for each test case, the execution time in milliseconds that your solution required to process the test case.
Once again, the objective is to maximize parents’ satisfaction with the conference schedule, and to minimize wasted time. The Challenge will be scored based on the number of penalty points accumulated by each entry. If a desired conference is not accommodated, you will accumulate 1-9 penalty points, depending on the strength of the parents’ desire for that conference as expressed in teachers.txt. If a parent has a gap in the conference schedule, where a conference is scheduled during periods N and N+2, but not in N+1, you will accumulate one penalty point for each unscheduled period in the gap. Similar penalty points will accumulate for gaps in the conference schedule for teachers. Finally, the penalty will be increased by 10% for each second of execution time used by your solution.
We’re going to make another attempt to broaden the development environments accepted for the Challenge, despite mixed success in the past. This will be a native PowerPC Challenge, using any of the following environments: CodeWarrior Pro, REALbasic, MetaCard, Revolution, or ProjectBuilder. You may use another development environment if I can arrange to obtain a copy – email firstname.lastname@example.org to check before you use something else. You can develop for Mac OS 9 or Mac OS X. Your submission should provide everyting needed to build your application.
Three Months Ago Winner
I mentioned above that we have had mixed success in experimenting with alternative development environments for the Challenge. That was certainly true in the September Challenge, where we asked readers to produce Nassi-Schneiderman diagrams using the environment of their choice. Perhaps because the Challenge focused on diagramming C/C++ code, no one submitted an entry using these alternative environments. Sadly, no one submitted a C/C++ entry either, so we have no winner for the Challenge this month. Remember, you can’t win if you don’t play!