1%Assume each task takes exactly 1 hour, and each time slot is 1 hour
    2
    3make_schedule:-schedule(breakfast,_),
    4           schedule(lunch,_),
    5           schedule(dinner,_),
    6           schedule(asp_coding_1,_),
    7           schedule(asp_coding_2,_),
    8           schedule(homework,_),
    9           schedule(homework_discussion,_),
   10           schedule(snack,_).
   11
   12constraint(breakfast,T):-T>=6,T<10.
   13constraint(lunch,T):-T>=11,T<13.
   14constraint(dinner,T):-T>=17,T<19.
   15constraint(snack,T):-schedule(lunch,T1),schedule(dinner,T2),T>T1,T<T2.
   16
   17constraint(homework_discussion,T):-schedule(homework,T1),T>T1.
   18           
   19constraint(asp_coding_1,_).
   20constraint(asp_coding_2,_).
   21constraint(homework,_).
   22
   23time_slot(X):-X>=0,X<24.
   24
   25%A task may or may not be scheduled at a specific time.
   26schedule(Task,Time):-time_slot(Time),constraint(Task,Time),not not_schedule(Task,Time).
   27not_schedule(Task,Time):-not