A-M baby

Task/Knapsack-problem-Continuous/Java/knapsack-problem-continuous-2.java

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+package hu.pj.alg;
+
+import hu.pj.obj.Item;
+import java.util.*;
+
+public class ContinuousKnapsack {
+
+    protected List<Item> itemList   = new ArrayList<Item>();
+    protected double maxWeight      = 0;
+    protected double solutionWeight = 0;
+    protected double profit         = 0;
+    protected boolean calculated    = false;
+
+    public ContinuousKnapsack() {}
+
+    public ContinuousKnapsack(double _maxWeight) {
+        setMaxWeight(_maxWeight);
+    }
+
+    public List<Item> calcSolution() {
+        int n = itemList.size();
+
+        setInitialStateForCalculation();
+        if (n > 0  &&  maxWeight > 0) {
+            Collections.sort(itemList);
+            for (int i = 0; (maxWeight - solutionWeight) > 0.0  &&  i < n; i++) {
+                Item item = itemList.get(i);
+                if (item.getWeight() >= (maxWeight - solutionWeight)) {
+                    item.setInKnapsack(maxWeight - solutionWeight);
+                    solutionWeight = maxWeight;
+                    profit += item.getInKnapsack() / item.getWeight() * item.getValue();
+                    break;
+                } else {
+                    item.setInKnapsack(item.getWeight());
+                    solutionWeight += item.getInKnapsack();
+                    profit += item.getValue();
+                }
+            }
+            calculated = true;
+        }
+
+        return itemList;
+    }
+
+    // add an item to the item list
+    public void add(String name, double weight, double value) {
+        if (name.equals(""))
+            name = "" + (itemList.size() + 1);
+        itemList.add(new Item(name, weight, value));
+        setInitialStateForCalculation();
+    }
+
+    public double getMaxWeight() {return maxWeight;}
+    public double getProfit() {return profit;}
+    public double getSolutionWeight() {return solutionWeight;}
+    public boolean isCalculated() {return calculated;}
+
+    public void setMaxWeight(double _maxWeight) {
+        maxWeight = Math.max(_maxWeight, 0);
+    }
+
+    // set the member with name "inKnapsack" by all items:
+    private void setInKnapsackByAll(double inKnapsack) {
+        for (Item item : itemList)
+            item.setInKnapsack(inKnapsack);
+    }
+
+    // set the data members of class in the state of starting the calculation:
+    protected void setInitialStateForCalculation() {
+        setInKnapsackByAll(-0.0001);
+        calculated     = false;
+        profit         = 0.0;
+        solutionWeight = 0.0;
+    }
+
+} // class