/** Finds the product combinations of numItems items with $1 of the totalPrice */
private void findProductCombination(
ArrayList<Product> productList, double target, ArrayList<Product> partial) {
// Keeping +-2 dollar as the price search window.
int priceBuffer = 2;
// if partial size > numItems, you already have too many items, so stop
if (partial.size() > itemCount) {
return;
}
double sum = 0;
for (Product x : partial) sum += x.getPrice();
if (Math.abs(sum - target) < priceBuffer
&& partial.size() == itemCount
&& desiredProductList.size() < 25) {
// if no price combos yet, just add it on
if (desiredProductList.size() == 0) {
desiredProductList.add(new Combination(partial, totalPrice));
}
// otherwise, check it against the most recent product combo to make sure you're not repeating
// TODO: check all product combos
else {
Combination testerCombo = desiredProductList.get(desiredProductList.size() - 1);
Combination partialCombo = new Combination(partial, totalPrice);
if (!partialCombo.equals(testerCombo)) {
desiredProductList.add(partialCombo);
}
}
}
// if sum is at or within $1 of target, then stop - done!
if (sum >= target + priceBuffer) {
return;
}
// otherwise, recursively continue adding another product to combo and test it
for (int i = 0; i < productList.size() && !(partial.size() == itemCount && sum < target); i++) {
ArrayList<Product> remaining = new ArrayList<Product>();
Product n = productList.get(i);
for (int j = i + 1; j < productList.size(); j++) {
remaining.add(productList.get(j));
}
ArrayList<Product> partial_rec = new ArrayList<Product>(partial);
partial_rec.add(n);
findProductCombination(remaining, target, partial_rec);
}
}
/** Returns the gift combinations that are closest to the total dollar amount */
@SuppressWarnings("unchecked")
public String getGiftCombos() throws IOException, ParseException {
// get products from API
System.out.println("Searching Zappos...");
this.findProducts();
// find combinations that work
this.findProductCombination(allProductList, totalPrice, new ArrayList<Product>());
Collections.sort(desiredProductList);
// see if you have any combos
if (desiredProductList.size() != 0) {
String toPrint = "\nDone!\n";
for (Combination x : desiredProductList) {
toPrint += x.toString() + "\n";
}
return toPrint;
} else {
return "No items matching your criteria. Try fewer items or higher price range.";
}
}