Adds the solution to Apply Discount Every N Orders

Java/.project

@@ -14,4 +14,15 @@
 	<natures>
 		<nature>org.eclipse.jdt.core.javanature</nature>
 	</natures>
+	<filteredResources>
+		<filter>
+			<id>1676076077872</id>
+			<name></name>
+			<type>30</type>
+			<matcher>
+				<id>org.eclipse.core.resources.regexFilterMatcher</id>
+				<arguments>node_modules|\.git|__CREATED_BY_JAVA_LANGUAGE_SERVER__</arguments>
+			</matcher>
+		</filter>
+	</filteredResources>
 </projectDescription>

Java/src/ApplyDiscountEveryNOrders.java

@@ -0,0 +1,40 @@
+import java.util.HashMap;
+import java.util.Map;
+
+class ApplyDiscountEveryNOrders {
+    private int n;
+    private int discount;
+    private int curr;
+    private Map<Integer, Integer> lookup;
+    public ApplyDiscountEveryNOrders(int n, int discount, int[] products, int[] prices) {
+        this.n = n;
+        this.discount = discount;
+        this.curr = 0;
+        this.lookup = new HashMap<>();
+
+        // Map<Integer, Integer> lookup = new HashMap<>();
+        for (int i = 0; i < products.length; i++) {
+        lookup.put(products[i], prices[i]);
+        }
+
+    }
+
+    public double getBill(int[] product, int[] amount) {
+        this.curr = (this.curr+1) % this.n;
+        double result = 0.0;
+        for (int i = 0; i < product.length; i++) {
+            int p = product[i];
+            Integer pp = this.lookup.get(p);
+            if(pp != null){
+                result += pp * amount[i];
+            }
+        }
+        return result * (curr == 0 ? (1.0 - (double)discount/100.0) : 1.0);
+    }
+}
+
+/**
+ * Your Cashier object will be instantiated and called as such:
+ * Cashier obj = new Cashier(n, discount, products, prices);
+ * double param_1 = obj.getBill(product,amount);
+ */