Knapsack in Java for Hacktober Issue #1

java_knapsack.java

@@ -0,0 +1,70 @@
+import java.util.Scanner;
+
+public class java_knapsack {
+
+  public static void main(String args[]) {
+    Scanner sc = new Scanner(System.in);
+    System.out.print("Knapsack Problem...\nEnter number of items: ");
+    int numberOfItems = sc.nextInt();
+    System.out.print("Enter maximum weight of the container: ");
+    int maxWeight = sc.nextInt();
+    int randomProfit[] = new int[numberOfItems];
+    int randomWeight[] = new int[numberOfItems];
+    int ascendingProfit[] = new int[numberOfItems];
+    int ascendingWeight[] = new int[numberOfItems];
+    int descendingProfit[] = new int[numberOfItems];
+    int descendingWeight[] = new int[numberOfItems];
+    System.out.println("Random Order");
+    System.out.print("Enter weights for " + numberOfItems + " items in random order(Spaces in betweeen): ");
+    for (int i = 0; i < numberOfItems; i++) {
+      randomWeight[i] = sc.nextInt();
+    }
+    System.out.print("Enter profits for corresponding " + numberOfItems + " items(Spaces in betweeen): ");
+    for (int i = 0; i < numberOfItems; i++) {
+      randomProfit[i] = sc.nextInt();
+    }
+    double randomTotal = fractionalKnapsack(randomProfit, randomWeight, maxWeight);
+    System.out.println("Total Profit: " + randomTotal);  
+  }
+
+  public static double fractionalKnapsack(int profit[], int weight[], int maxWeight) {
+    double profitPerWeight[] = new double[profit.length];
+    int maxPW = -1;
+    double totalProfit = 0;
+    int j;
+    for (int i = 0; i < profit.length; i++) {
+      profitPerWeight[i] = (double)profit[i] / (double)weight[i];  
+    }
+    while (true) {
+      j = 0;
+      while (j < profit.length) {
+        if (weight[j] > 0) {
+          maxPW = j;
+          break;
+        }
+        j++;
+      }
+      if (j == profit.length) {
+        break; 
+      }
+      for (int i = j + 1; i < profit.length; i++) {
+        if (profitPerWeight[i] > profitPerWeight[maxPW] && weight[i] > 0) {
+          maxPW = i; 
+        }        
+      }      
+      if (weight[maxPW] <= maxWeight) {
+        maxWeight -= weight[maxPW];
+        totalProfit += profit[maxPW];
+        weight[maxPW] = 0;
+        if (maxWeight == 0) {
+          break;
+        }
+      } else {
+        totalProfit += maxWeight * profitPerWeight[maxPW];
+        break;
+      }
+    }
+    return totalProfit;
+  }
+
+}