database
visited_state(integer,integer)
predicates
state(integer,integer)
clauses
state(2,0).
state(X,Y):- X < 4,
not(visited_state(4,Y)),
assert(visited_state(X,Y)),
write("Fill the 4-Gallon Jug: (",X,",",Y,") --> (", 4,",",Y,")\n"),
state(4,Y).
state(X,Y):- Y < 3,
not(visited_state(X,3)),
assert(visited_state(X,Y)),
write("Fill the 3-Gallon Jug: (", X,",",Y,") --> (", X,",",3,")\n"),
state(X,3).
state(X,Y):- X > 0,
not(visited_state(0,Y)),
assert(visited_state(X,Y)),
write("Empty the 4-Gallon jug on ground: (", X,",",Y,") --> (", 0,",",Y,")\n"),
state(0,Y).
state(X,Y):- Y > 0,
not(visited_state(X,0)),
assert(visited_state(X,0)),
write("Empty the 3-Gallon jug on ground: (", X,",",Y,") --> (", X,",",0,")\n"),
state(X,0).
state(X,Y):- X + Y >= 4,
Y > 0,
NEW_Y = Y - (4 - X),
not(visited_state(4,NEW_Y)),
assert(visited_state(X,Y)),
write("Pour water from 3-Gallon jug to 4-gallon until it is full: (", X,",",Y,") --> (", 4,",",NEW_Y,")\n"),
state(4,NEW_Y).
state(X,Y):- X + Y >=3,
X > 0,
NEW_X = X - (3 - Y),
not(visited_state(X,3)),
assert(visited_state(X,Y)),
write("Pour water from 4-Gallon jug to 3-gallon until it is full: (", X,",",Y,") --> (", NEW_X,",",3,")\n"),
state(NEW_X,3).
state(X,Y):- X + Y <=4,
Y > 0,
NEW_X = X + Y,
not(visited_state(NEW_X,0)),
assert(visited_state(X,Y)),
write("Pour all the water from 3-Gallon jug to 4-gallon: (", X,",",Y,") --> (", NEW_X,",",0,")\n"),
state(NEW_X,0).
state(X,Y):- X+Y<=3,
X > 0,
NEW_Y = X + Y,
not(visited_state(0,NEW_Y)),
assert(visited_state(X,Y)),
write("Pour all the water from 4-Gallon jug to 3-gallon: (", X,",",Y,") --> (", 0,",",NEW_Y,")\n"),
state(0,NEW_Y).
state(0,2):- not(visited_state(2,0)),
assert(visited_state(0,2)),
write("Pour 2 gallons from 3-Gallon jug to 4-gallon: (", 0,",",2,") --> (", 2,",",0,")\n"),
state(2,0).
state(2,Y):- not(visited_state(0,Y)),
assert(visited_state(2,Y)),
write("Empty 2 gallons from 4-Gallon jug on the ground: (", 2,",",Y,") --> (", 0,",",Y,")\n"),
state(0,Y).
goal
makewindow(1,2,3,"4-3 Water Jug Problem",0,0,25,80),
state(0,0).
Output
+-----------------------------4-3 Water Jug Problem--------------------------+
¦Fill the 4-Gallon Jug: (0,0) --> (4,0) ¦
¦Fill the 3-Gallon Jug: (4,0) --> (4,3) ¦
¦Empty the 4-Gallon jug on ground: (4,3) --> (0,3) ¦
¦Pour all the water from 3-Gallon jug to 4-gallon: (0,3) --> (3,0) ¦
¦Fill the 3-Gallon Jug: (3,0) --> (3,3) ¦
¦Pour water from 3-Gallon jug to 4-gallon until it is full: (3,3) --> (4,2) ¦
¦Empty the 4-Gallon jug on ground: (4,2) --> (0,2) ¦
¦Pour all the water from 3-Gallon jug to 4-gallon: (0,2) --> (2,0) ¦
¦ ¦
¦Press the SPACE bar ¦
¦ ¦
¦ ¦
¦ ¦
+----------------------------------------------------------------------------+