Sangwook on October 1, 2015
I don't understand why M is the only worker who can work before J.
Isn't J also possible worker before J?
"On any given day, an employee works on exactly one work piece."
So, since there is no condition limiting 'each four employee must work on four consecutive days,' isn't the following possible?:
W4 J. J. J. J
Mon. Tu. We. Th
Melody on October 2, 2015
Sangwook on October 2, 2015