Fractional_Knapsack_Problem.java: Implement Fractional Knapsack Probl…

…em in java

Algorithms/Dynamic Programming/Fractional_Knapsack_Problem.java

@@ -0,0 +1,82 @@
+import java.util.Arrays; 
+import java.util.Comparator; 
+
+public class FractionalKnapSack 
+{ 
+	// Time complexity O(n log n) 
+	public static void main(String[] args) 
+	{ 
+		int[] wt = {10, 40, 20, 30}; 
+		int[] val = {60, 40, 100, 120}; 
+		int capacity = 50; 
+
+		double maxValue = getMaxValue(wt, val, capacity); 
+		System.out.println("Maximum value we can obtain = " + 
+							maxValue); 
+
+	} 
+
+	// function to get maximum value 
+	private static double getMaxValue(int[] wt, 
+						int[] val, int capacity) 
+	{ 
+		ItemValue[] iVal = new ItemValue[wt.length]; 
+
+		for(int i = 0; i < wt.length; i++) 
+		{ 
+			iVal[i] = new ItemValue(wt[i], val[i], i); 
+		} 
+
+		//sorting items by value; 
+		Arrays.sort(iVal, new Comparator<ItemValue>() 
+		{ 
+			@Override
+			public int compare(ItemValue o1, ItemValue o2) 
+			{ 
+				return o2.cost.compareTo(o1.cost) ; 
+			} 
+		}); 
+
+
+		double totalValue = 0d; 
+
+		for(ItemValue i: iVal) 
+		{ 
+
+			int curWt = (int) i.wt; 
+			int curVal = (int) i.val; 
+
+			if (capacity - curWt >= 0) 
+			{ 
+				// this weight can be picked while 
+				capacity = capacity-curWt; 
+				totalValue += curVal; 
+
+			} 
+			else
+			{ 
+				// item cant be picked whole 
+				double fraction = ((double)capacity/(double)curWt); 
+				totalValue += (curVal*fraction); 
+				capacity = (int)(capacity - (curWt*fraction)); 
+				break; 
+			} 
+
+
+		} 
+
+		return totalValue; 
+	}  
+	static class ItemValue 
+	{ 
+		Double cost; 
+		double wt, val, ind;  
+		public ItemValue(int wt, int val, int ind) 
+		{ 
+			this.wt = wt; 
+			this.val = val; 
+			this.ind = ind; 
+			cost = new Double(val/wt ); 
+		} 
+	} 
+}