timetabling:
course sections assigned (1 row per student, 1 col per course):
1 1 1 3
1 3 2 2
2 2 3 3
2 2 3 3
3 1 2 2
2 1 2 1
2 2 1 1
2 2 1 2
2 1 1 2
1 1 2 1
1 2 1 2
2 2 2 3
1 2 1 3
2 2 2 1
1 2 1 1
2 2 2 1
2 1 1 3
2 1 2 2
2 2 1 3
1 1 3 1
times of each section (1 row per course, 1 col per section):
3 4 2
3 5 2
1 3 1
2 1 1
4 1 1
1 1 1
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