Added Vedang's fractional knapsack code.

2025-10-12 15:05:47 +05:30
parent fed68211f0
commit 5adfd0301a
1 changed files with 83 additions and 0 deletions
@@ -0,0 +1,83 @@
+import java.util.*;
+
+public class Code_A3 { // Main public class must match filename
+    static class Item {
+        int value, weight;
+        double ratio;
+
+        Item(int value, int weight) {
+            this.value = value;
+            this.weight = weight;
+            this.ratio = (double) value / weight;
+        }
+    }
+
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+        List<Item> items = new ArrayList<>();
+        int choice;
+
+        while (true) {
+            System.out.println("\n=== Fractional Knapsack Menu ===");
+            System.out.println("1. Enter items");
+            System.out.println("2. Solve fractional knapsack");
+            System.out.println("3. Exit");
+            System.out.print("Enter your choice: ");
+            choice = sc.nextInt();
+
+            switch (choice) {
+                case 1:
+                    items.clear();
+                    System.out.print("Enter number of items: ");
+                    int n = sc.nextInt();
+                    for (int i = 0; i < n; i++) {
+                        System.out.print("Item " + (i + 1) + " value: ");
+                        int v = sc.nextInt();
+                        System.out.print("Item " + (i + 1) + " weight: ");
+                        int w = sc.nextInt();
+                        items.add(new Item(v, w));
+                    }
+                    break;
+
+                case 2:
+                    if (items.isEmpty()) {
+                        System.out.println("Please enter items first!");
+                        break;
+                    }
+                    System.out.print("Enter knapsack capacity: ");
+                    int capacity = sc.nextInt();
+
+                    // Sort by value-to-weight ratio
+                    items.sort((a, b) -> Double.compare(b.ratio, a.ratio));
+
+                    double totalValue = 0;
+                    int remaining = capacity;
+                    System.out.println("\nItems taken (value/weight fraction):");
+                    for (Item item : items) {
+                        if (remaining == 0) break;
+                        if (item.weight <= remaining) {
+                            System.out.println(item.value + "/" + item.weight + " -> Full");
+                            totalValue += item.value;
+                            remaining -= item.weight;
+                        } else {
+                            double fraction = (double) remaining / item.weight;
+                            System.out.println(item.value + "/" + item.weight + " -> " + (fraction * 100) + "%");
+                            totalValue += item.value * fraction;
+                            remaining = 0;
+                        }
+                    }
+
+                    System.out.printf("Maximum total value in knapsack: %.2f\n", totalValue);
+                    break;
+
+                case 3:
+                    System.out.println("Exiting program. Goodbye!");
+                    sc.close();
+                    return;
+
+                default:
+                    System.out.println("Invalid choice!");
+            }
+        }
+    }
+}