//The riddle I wanted to check my solution for, goes as follows: // "We have 12 balls and a pair of scales. All of them are of the same shape, size and more importantly weight (technically mass), but, one of them is either lighter or heavier than the others. How can we determine the odd one out AND its heavier-or-lighter-ness with ONLY THREE weighings." //update: now it has comments!! //update 2: now, I realized it doesn't even work!! (It doesn't solve the riddle in only three weighings.) //update 3: now, it does finally work!! #include #include using namespace std; int main() { //while(true) { //initializing all the balls int a1, a2, a3, a4, b1, b2, b3, b4, c1, c2, c3, c4; a1 = a2 = a3 = a4 = b1 = b2 = b3 = b4 = c1 = c2 = c3 = c4 = 0; //declaring the preparations for the special ball int special, specialty = 0; //dialog cout << "Which ball do you want to make unique? (1, 2, 5, 8 ...)" << endl; cin >> special; cout << endl << endl; //wrong input error while(special < 1 || special > 12) { cout << "Wrong input. Please, try again.\n"; cin >> special; cout << endl; cout << endl; } //more dialog cout << "And, should it be \"heavier\" or \"lighter\"? Enter 1 for heavier and -1 for lighter." << endl; ; cin >> specialty; cout << endl << endl; //wrong input error while(specialty != 1 && specialty != -1) { cout << "Wrong input. Please, try again.\n"; cin >> specialty; cout << endl; cout << endl; } //making the user-inputted ball, special, which I found out doesn't work with balls[special] += specialty; because then, it would just add a ±1 to the array that holds the balls on the index of special and it wouldn't add anything to the "a1, a2, ...". Maybe it would work well with enumerations but I don't know about them that much so, yeah... switch(special) { case 1: a1 += specialty; break; case 2: a2 += specialty; break; case 3: a3 += specialty; break; case 4: a4 += specialty; break; case 5: b1 += specialty; break; case 6: b2 += specialty; break; case 7: b3 += specialty; break; case 8: b4 += specialty; break; case 9: c1 += specialty; break; case 10: c2 += specialty; break; case 11: c3 += specialty; break; case 12: c4 += specialty; break; } //declaring the classifications necessary for finding the solution int a = a1 + a2 + a3; int b = b1 + b2 + b3; int c = c1 + c2 + c3; int A = a + a4; int B = b + b4; int C = c + c4; //this last one's not really needed with the current formula; keeping it for the sake of symmetry //declaring two strings to store the specifications of the special one in them, after the comparison is done string ball, weight; //The Solution (probably not easy to read, but drawing diagrams will help) if (A > B) { if (a1 + c2 + b3 > b1 + b2 + a3) { if (a1 + b1 > c1 + c2) { weight = "h"; ball = "a1"; } else if (a1 + b1 < c1 + c2) { weight = "l"; ball = "b1"; } else if (a1 + b1 == c1 + c2) { weight = "l"; ball = "b2"; } } if (a1 + c2 + b3 < b1 + b2 + a3) { if (a3 > c3) { weight = "h"; ball = "a3"; } else if (a3 == c3) { weight = "l"; ball = "b3"; } } if (a1 + c2 + b3 == b1 + b2 + a3) { if (a2 + b4 > c1 + c2) { weight = "h"; ball = "a2"; } else if (a2 + b4 < c1 + c2) { weight = "l"; ball = "b4"; } else if (a2 + b4 == c1 + c2) { weight = "h"; ball = "a4"; } } } if (A < B) { if (b1 + c2 + a3 > a1 + a2 + b3) { if (b1 + a1 > c1 + c2) { weight = "h"; ball = "b1"; } else if (b1 + a1 < c1 + c2) { weight = "l"; ball = "a1"; } else if (b1 + a1 == c1 + c2) { weight = "l"; ball = "a2"; } } if (b1 + c2 + a3 < a1 + a2 + b3) { if (b3 > c3) { weight = "h"; ball = "b3"; } else if (b3 == c3) { weight = "l"; ball = "a3"; } } if (b1 + c2 + a3 == a1 + a2 + b3) { if (b2 + a4 > c1 + c2) { weight = "h"; ball = "b2"; } else if (b2 + a4 < c1 + c2) { weight = "l"; ball = "a4"; } else if (b2 + a4 == c1 + c2) { weight = "h"; ball = "b4"; } } } if (A == B) { if (c == a) { ball = "c4"; if (c4 > a4) {weight = "h"; } else if (c4 < a4) { weight = "l"; } } else if (c < a) { weight = "l"; if (c1 < c2) { ball = "c1"; } else if (c1 > c2) { ball = "c2"; } else { ball = "c3"; } } else if (c > a) { weight = "h"; if (c1 > c2) { ball = "c1"; } else if (c1 < c2) { ball = "c2"; } else { ball = "c3"; } } } //printing out the solution-ball to the screen if (weight == "h") cout << ball << " is heavier"; else if (weight == "l") cout << ball << " is lighter"; cout << endl << endl << endl << endl; // } return 0; }

Problem Solution Checker # 1