#include char *NationS[] = {"British", "Swedish", "Danish", "Norvegian", "German"}; enum Nation {British, Swedish, Danish, Norvegian, German}; char *NumberS[] = {"One", "Two", "Three", "Four", "Five"}; enum Number {One, Two, Three, Four, Five}; char *ColourS[] = {"Red", "Green", "Blue", "White", "Yellow"}; enum Colour {Red, Green, Blue, White, Yellow}; char *DrinkS[] = {"Milk", "Coffee", "Water", "Beer", "Tea"}; enum Drink {Milk, Coffee, Water, Beer, Tea}; char *SmokeS[] = {"PallMall", "Dunhill", "Blend", "BlueMaster", "Prince"}; enum Smoke {PallMall, Dunhill, Blend, BlueMaster, Prince}; char *PetS[] = {"Dog", "Cat", "Fish", "Horse", "Bird"}; enum Pet {Dog, Cat, Fish, Horse, Bird}; #define TRUE 1 #define FALSE 0 void myprint(char *ptr, char **s) { printf("%12s%12s%12s%12s%12s\n", s[ptr[0]], s[ptr[1]], s[ptr[2]], s[ptr[3]], s[ptr[4]]); } char perms[][5] = { { 4, 3, 2, 1, 0}, { 3, 4, 2, 1, 0}, { 4, 2, 3, 1, 0}, { 2, 4, 3, 1, 0}, { 3, 2, 4, 1, 0}, { 2, 3, 4, 1, 0}, { 4, 3, 1, 2, 0}, { 3, 4, 1, 2, 0}, { 4, 1, 3, 2, 0}, { 1, 4, 3, 2, 0}, { 3, 1, 4, 2, 0}, { 1, 3, 4, 2, 0}, { 4, 2, 1, 3, 0}, { 2, 4, 1, 3, 0}, { 4, 1, 2, 3, 0}, { 1, 4, 2, 3, 0}, { 2, 1, 4, 3, 0}, { 1, 2, 4, 3, 0}, { 3, 2, 1, 4, 0}, { 2, 3, 1, 4, 0}, { 3, 1, 2, 4, 0}, { 1, 3, 2, 4, 0}, { 2, 1, 3, 4, 0}, { 1, 2, 3, 4, 0}, { 4, 3, 2, 0, 1}, { 3, 4, 2, 0, 1}, { 4, 2, 3, 0, 1}, { 2, 4, 3, 0, 1}, { 3, 2, 4, 0, 1}, { 2, 3, 4, 0, 1}, { 4, 3, 0, 2, 1}, { 3, 4, 0, 2, 1}, { 4, 0, 3, 2, 1}, { 0, 4, 3, 2, 1}, { 3, 0, 4, 2, 1}, { 0, 3, 4, 2, 1}, { 4, 2, 0, 3, 1}, { 2, 4, 0, 3, 1}, { 4, 0, 2, 3, 1}, { 0, 4, 2, 3, 1}, { 2, 0, 4, 3, 1}, { 0, 2, 4, 3, 1}, { 3, 2, 0, 4, 1}, { 2, 3, 0, 4, 1}, { 3, 0, 2, 4, 1}, { 0, 3, 2, 4, 1}, { 2, 0, 3, 4, 1}, { 0, 2, 3, 4, 1}, { 4, 3, 1, 0, 2}, { 3, 4, 1, 0, 2}, { 4, 1, 3, 0, 2}, { 1, 4, 3, 0, 2}, { 3, 1, 4, 0, 2}, { 1, 3, 4, 0, 2}, { 4, 3, 0, 1, 2}, { 3, 4, 0, 1, 2}, { 4, 0, 3, 1, 2}, { 0, 4, 3, 1, 2}, { 3, 0, 4, 1, 2}, { 0, 3, 4, 1, 2}, { 4, 1, 0, 3, 2}, { 1, 4, 0, 3, 2}, { 4, 0, 1, 3, 2}, { 0, 4, 1, 3, 2}, { 1, 0, 4, 3, 2}, { 0, 1, 4, 3, 2}, { 3, 1, 0, 4, 2}, { 1, 3, 0, 4, 2}, { 3, 0, 1, 4, 2}, { 0, 3, 1, 4, 2}, { 1, 0, 3, 4, 2}, { 0, 1, 3, 4, 2}, { 4, 2, 1, 0, 3}, { 2, 4, 1, 0, 3}, { 4, 1, 2, 0, 3}, { 1, 4, 2, 0, 3}, { 2, 1, 4, 0, 3}, { 1, 2, 4, 0, 3}, { 4, 2, 0, 1, 3}, { 2, 4, 0, 1, 3}, { 4, 0, 2, 1, 3}, { 0, 4, 2, 1, 3}, { 2, 0, 4, 1, 3}, { 0, 2, 4, 1, 3}, { 4, 1, 0, 2, 3}, { 1, 4, 0, 2, 3}, { 4, 0, 1, 2, 3}, { 0, 4, 1, 2, 3}, { 1, 0, 4, 2, 3}, { 0, 1, 4, 2, 3}, { 2, 1, 0, 4, 3}, { 1, 2, 0, 4, 3}, { 2, 0, 1, 4, 3}, { 0, 2, 1, 4, 3}, { 1, 0, 2, 4, 3}, { 0, 1, 2, 4, 3}, { 3, 2, 1, 0, 4}, { 2, 3, 1, 0, 4}, { 3, 1, 2, 0, 4}, { 1, 3, 2, 0, 4}, { 2, 1, 3, 0, 4}, { 1, 2, 3, 0, 4}, { 3, 2, 0, 1, 4}, { 2, 3, 0, 1, 4}, { 3, 0, 2, 1, 4}, { 0, 3, 2, 1, 4}, { 2, 0, 3, 1, 4}, { 0, 2, 3, 1, 4}, { 3, 1, 0, 2, 4}, { 1, 3, 0, 2, 4}, { 3, 0, 1, 2, 4}, { 0, 3, 1, 2, 4}, { 1, 0, 3, 2, 4}, { 0, 1, 3, 2, 4}, { 2, 1, 0, 3, 4}, { 1, 2, 0, 3, 4}, { 2, 0, 1, 3, 4}, { 0, 2, 1, 3, 4}, { 1, 0, 2, 3, 4}, { 0, 1, 2, 3, 4} }; char possible(char *number, char *colour, char* drink, char *smoke, char *pet) { // Rules, with the rule number as a comment // single property rules if(number != NULL && number[Norvegian] != One) // 9 return FALSE; if(colour != NULL && colour[British] != Red) // 1 return FALSE; if(drink != NULL && drink[Danish] != Tea) // 3 return FALSE; if(smoke != NULL && smoke[German] != Prince) // 13 return FALSE; if(pet != NULL && pet[Swedish] != Dog) // 2 return FALSE; // only check complicated rules, if everything is defined if(number == NULL || colour == NULL || drink == NULL || smoke == NULL || pet == NULL) return TRUE; // double property rules int i, j, diff; for(i = 0; i < 5; i++){ if(colour[i] == Green && drink[i] != Coffee) // 5 return FALSE; if(smoke[i] == PallMall && pet[i] != Bird) // 6 return FALSE; if(colour[i] == Yellow && smoke[i] != Dunhill) // 7 return FALSE; if(number[i] == Three && drink[i] != Milk) // 8 return FALSE; if(smoke[i] == BlueMaster && drink[i] != Beer) // 12 return FALSE; if(colour[i] == Blue && number[i] != Two) // 14 return FALSE; // double person double property rules for(j = 0; j < 5; j++){ if(colour[i] == Green && colour[j] == White && number[j] - number[i] != 1) // 4 return FALSE; diff = number[i]-number[j]; if(diff < 0) diff = -diff; if(smoke[i] == Blend && pet[j] == Cat && diff != 1) // 10 return FALSE; if(pet[i] == Horse && smoke[j] == Dunhill && diff != 1) // 11 return FALSE; if(smoke[i] == Blend && drink[j] == Water && diff != 1) // 15 return FALSE; } } return TRUE; } main() { char nation[5] = {British, Swedish, Danish, Norvegian, German}; char *number = NULL; char *colour = NULL; char *drink = NULL; char *smoke = NULL; char *pet = NULL; char i1, i2, i3, i4, i5; for(i1 = 0; i1 < 120; i1++){ number = perms[i1]; if(possible(number, colour, drink, smoke, pet)) for(i2 = 0; i2 < 120; i2++){ colour = perms[i2]; if(possible(number, colour, drink, smoke, pet)) for(i3 = 0; i3 < 120; i3++){ drink = perms[i3]; if(possible(number, colour, drink, smoke, pet)) for(i4 = 0; i4 < 120; i4++){ smoke = perms[i4]; if(possible(number, colour, drink, smoke, pet)) for(i5 = 0; i5 < 120; i5++){ pet = perms[i5]; if(possible(number, colour, drink, smoke, pet)){ // woo-hoo! printf("Found a solution:\n"); printf("Nation: "); myprint(nation, NationS); printf("Number: "); myprint(number, NumberS); printf("Colour: "); myprint(colour, ColourS); printf("Drink : "); myprint(drink, DrinkS); printf("Smoke : "); myprint(smoke, SmokeS); printf("Pet : "); myprint(pet, PetS); printf("\n"); } } pet = NULL; } smoke = NULL; } drink = NULL; } colour = NULL; } }