diff -r d59bea55db9b -r c445c931472f examples/zebra.mod --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/examples/zebra.mod Mon Dec 06 13:09:21 2010 +0100 @@ -0,0 +1,151 @@ +/* ZEBRA, Who Owns the Zebra? */ + +/* Written in GNU MathProg by Andrew Makhorin */ + +######################################################################## +# The Zebra Puzzle is a well-known logic puzzle. +# +# It is often called "Einstein's Puzzle" or "Einstein's Riddle" +# because it is said to have been invented by Albert Einstein as a boy, +# with the common claim that Einstein said "only 2 percent of the +# world's population can solve". It is also sometimes attributed to +# Lewis Carroll. However, there is no known evidence for Einstein's or +# Carroll's authorship. +# +# There are several versions of this puzzle. The version below is +# quoted from the first known publication in Life International +# magazine on December 17, 1962. +# +# 1. There are five houses. +# 2. The Englishman lives in the red house. +# 3. The Spaniard owns the dog. +# 4. Coffee is drunk in the green house. +# 5. The Ukrainian drinks tea. +# 6. The green house is immediately to the right of the ivory house. +# 7. The Old Gold smoker owns snails. +# 8. Kools are smoked in the yellow house. +# 9. Milk is drunk in the middle house. +# 10. The Norwegian lives in the first house. +# 11. The man who smokes Chesterfields lives in the house next to the +# man with the fox. +# 12. Kools are smoked in the house next to the house where the horse +# is kept. +# 13. The Lucky Strike smoker drinks orange juice. +# 14. The Japanese smokes Parliaments. +# 15. The Norwegian lives next to the blue house. +# +# Now, who drinks water? Who owns the zebra? +# +# In the interest of clarity, it must be added that each of the five +# houses is painted a different color, and their inhabitants are of +# different national extractions, own different pets, drink different +# beverages and smoke different brands of American cigarettes. One +# other thing: In statement 6, right means your right. +# +# (From Wikipedia, the free encyclopedia.) +######################################################################## + +set HOUSE := { 1..5 }; + +set COLOR := { "blue", "green", "ivory", "red", "yellow" }; + +set NATIONALITY := { "Englishman", "Japanese", "Norwegian", "Spaniard", + "Ukranian" }; + +set DRINK := { "coffee", "milk", "orange_juice", "tea", "water" }; + +set SMOKE := { "Chesterfield", "Kools", "Lucky_Strike", "Old_Gold", + "Parliament" }; + +set PET := { "dog", "fox", "horse", "snails", "zebra" }; + +var color{HOUSE, COLOR}, binary; +c1{h in HOUSE}: sum{c in COLOR} color[h,c] = 1; +c2{c in COLOR}: sum{h in HOUSE} color[h,c] = 1; + +var nationality{HOUSE, NATIONALITY}, binary; +n1{h in HOUSE}: sum{n in NATIONALITY} nationality[h,n] = 1; +n2{n in NATIONALITY}: sum{h in HOUSE} nationality[h,n] = 1; + +var drink{HOUSE, DRINK}, binary; +d1{h in HOUSE}: sum{d in DRINK} drink[h,d] = 1; +d2{d in DRINK}: sum{h in HOUSE} drink[h,d] = 1; + +var smoke{HOUSE, SMOKE}, binary; +s1{h in HOUSE}: sum{s in SMOKE} smoke[h,s] = 1; +s2{s in SMOKE}: sum{h in HOUSE} smoke[h,s] = 1; + +var pet{HOUSE, PET}, binary; +p1{h in HOUSE}: sum{p in PET} pet[h,p] = 1; +p2{p in PET}: sum{h in HOUSE} pet[h,p] = 1; + +/* the Englishman lives in the red house */ +f2{h in HOUSE}: nationality[h,"Englishman"] = color[h,"red"]; + +/* the Spaniard owns the dog */ +f3{h in HOUSE}: nationality[h,"Spaniard"] = pet[h,"dog"]; + +/* coffee is drunk in the green house */ +f4{h in HOUSE}: drink[h,"coffee"] = color[h,"green"]; + +/* the Ukrainian drinks tea */ +f5{h in HOUSE}: nationality[h,"Ukranian"] = drink[h,"tea"]; + +/* the green house is immediately to the right of the ivory house */ +f6{h in HOUSE}: + color[h,"green"] = if h = 1 then 0 else color[h-1,"ivory"]; + +/* the Old Gold smoker owns snails */ +f7{h in HOUSE}: smoke[h,"Old_Gold"] = pet[h,"snails"]; + +/* Kools are smoked in the yellow house */ +f8{h in HOUSE}: smoke[h,"Kools"] = color[h,"yellow"]; + +/* milk is drunk in the middle house */ +f9: drink[3,"milk"] = 1; + +/* the Norwegian lives in the first house */ +f10: nationality[1,"Norwegian"] = 1; + +/* the man who smokes Chesterfields lives in the house next to the man + with the fox */ +f11{h in HOUSE}: + (1 - smoke[h,"Chesterfield"]) + + (if h = 1 then 0 else pet[h-1,"fox"]) + + (if h = 5 then 0 else pet[h+1,"fox"]) >= 1; + +/* Kools are smoked in the house next to the house where the horse is + kept */ +f12{h in HOUSE}: + (1 - smoke[h,"Kools"]) + + (if h = 1 then 0 else pet[h-1,"horse"]) + + (if h = 5 then 0 else pet[h+1,"horse"]) >= 1; + +/* the Lucky Strike smoker drinks orange juice */ +f13{h in HOUSE}: smoke[h,"Lucky_Strike"] = drink[h,"orange_juice"]; + +/* the Japanese smokes Parliaments */ +f14{h in HOUSE}: nationality[h,"Japanese"] = smoke[h,"Parliament"]; + +/* the Norwegian lives next to the blue house */ +f15{h in HOUSE}: + (1 - nationality[h,"Norwegian"]) + + (if h = 1 then 0 else color[h-1,"blue"]) + + (if h = 5 then 0 else color[h+1,"blue"]) >= 1; + +solve; + +printf "\n"; +printf "HOUSE COLOR NATIONALITY DRINK SMOKE PET\n"; +for {h in HOUSE} +{ printf "%5d", h; + printf{c in COLOR: color[h,c]} " %-6s", c; + printf{n in NATIONALITY: nationality[h,n]} " %-11s", n; + printf{d in DRINK: drink[h,d]} " %-12s", d; + printf{s in SMOKE: smoke[h,s]} " %-12s", s; + printf{p in PET: pet[h,p]} " %-6s", p; + printf "\n"; +} +printf "\n"; + +end;