CODEWITHSUNDEEP
javaiteration
ollym
ollym

Reputation: 143

How to calculate efficiently using every combination of a String, Integer pair where the Integer has a maxiumum in Java?

Imagine you have 3 items: a pen, a box and a car. You can have up to 9 pens, up to 5 boxes and up to 2 cars. How do you calculate the total value of every combination of items you could have?

Here's the code I currently have:

        int maxPens = 9;
        int maxBoxes = 5;
        int maxCars = 2;

        Double penPrice = 1.5;
        Double boxPrice = 50.0;
        Double carPrice = 150.0;

        int penCount = 0;
        int boxCount = 0;
        int carCount = 0;
        int totalCount = 1;

        while (penCount <= maxPens) {
            boxCount = 0;
            while (boxCount <= maxBoxes) {
                carCount = 0;
                while (carCount <= maxCars) {
                    Double totalPrice = (penCount * penPrice) + (boxCount * boxPrice) + (carCount * carPrice);
                    System.out.println(totalCount + " = " + totalPrice);

                    totalCount++;

                    carCount++;
                }
                boxCount++;
            }
            penCount++;
        }

This works and gives the output as the count of the combination, plus the total price, but feels really messy and if I then want to add another item I have to add more repeating into the method. Is it possible, for example, to do this using Maps where you might have:

Map<String, Integer> maxCountMap = new HashMap<String, Integer>();
Map<String, Double> priceMap = new HashMap<String, Integer>();

and iterate through these?

Upvotes: 1

Views: 46

Answers (1)

Daniel Stradowski
Daniel Stradowski

Reputation: 3484

You can iterate through Map, but in my opinion the cleanest solution is to create a new class Item:

public class Item {
   String name;
   int max;
   double price;

   Item(String name, int max, double price) {
       this.name = name;   
       this.max = max
       this.price = price;    
   }

}

This class should contain getters and setters.

And use for loop instead of while:

Item pen = new Item(Pen, 5, 1.5)
Item box = new Item(Box, 5, 50.0)
Item car = new Item(Car, 2, 150.0)

for (int i; i<=pen.getMax; i++){
  for (int j; j<=box.getMax; j++){
    for (int k; k<=car.getMax; k++){
      Double totalPrice = (i * pen.getPrice()) + (j * box.getPrice()) + (k * car.getPrice());
      int total = i+j+k;
      System.out.println(total + " = " + totalPrice);
    }
  }
}

Upvotes: 1

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