private boolean checkValidity() {
int answer = mOperation.getResult();
numbers.clear();
for (Cell cell : cells.values()) {
Point p = cell.location();
numbers.add(mLogic.getValue(p.y, p.x));
}
// first check to make sure no elements are zero to avoid early
// exit errors (e.g., solution = 3, cage is (3,)
// because default (missing values are zero)
// also prevent division by zero errors
for (Integer i : numbers) {
if (i == 0) {
return false;
}
}
if (mOperation.isAdd()) {
int sum = 0;
for (Integer i : numbers) {
sum += i;
}
return answer == sum;
} else if (mOperation.isMultiply()) {
int product = 1;
for (Integer i : numbers) {
product *= i;
}
return product == answer;
} else if (mOperation.isSubtract()) {
return permuteSubtractions(answer, numbers, 0);
} else if (mOperation.isDivide()) {
// try all the possible combinations
// don't just check against the solution. That would make
// it to easy for a player to fill in missing values
// by eliminating order-based guesses for them by showing
// solved cages for only one possible solution out of many
// (e.g, solution = 2 (4,2) might be ok but (2,4) would not
return permuteDivision(answer, numbers, 0);
} else if (numbers.size() == 1) {
return answer == numbers.get(0);
}
return false;
}
