add 1357

fishercoder1534 · fishercoder1534 · commit 58abb75be413 · 2020-02-22T09:09:15.000-08:00
diff --git a/README.md b/README.md
@@ -8,6 +8,7 @@ _If you like this project, please leave me a star._ &#9733;
 
 |  #  |      Title     |   Solutions   | Video  | Difficulty  | Tag                   
 |-----|----------------|---------------|--------|-------------|-------------
+|1357|[Apply Discount Every n Orders](https://leetcode.com/problems/apply-discount-every-n-orders/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1357.java) | |Medium|Design|
 |1356|[Sort Integers by The Number of 1 Bits](https://leetcode.com/problems/sort-integers-by-the-number-of-1-bits/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1356.java) | |Easy|Sort, Bit Manipulation|
 |1354|[Construct Target Array With Multiple Sums](https://leetcode.com/problems/construct-target-array-with-multiple-sums/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1354.java) | |Hard|Greedy|
 |1353|[Maximum Number of Events That Can Be Attended](https://leetcode.com/problems/maximum-number-of-events-that-can-be-attended/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1353.java) | |Medium|Greedy, Sort, Segment Tree|
diff --git a/src/main/java/com/fishercoder/solutions/_1357.java b/src/main/java/com/fishercoder/solutions/_1357.java
@@ -0,0 +1,87 @@
+package com.fishercoder.solutions;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * 1357. Apply Discount Every n Orders
+ *
+ * There is a sale in a supermarket, there will be a discount every n customer.
+ * There are some products in the supermarket where the id of the i-th product is products[i] and the price per unit of this product is prices[i].
+ * The system will count the number of customers and when the n-th customer arrive he/she will have a discount on the bill.
+ * (i.e if the cost is x the new cost is x - (discount * x) / 100). Then the system will start counting customers again.
+ * The customer orders a certain amount of each product where product[i] is the id of the i-th product the customer ordered and
+ * amount[i] is the number of units the customer ordered of that product.
+ *
+ * Implement the Cashier class:
+ * Cashier(int n, int discount, int[] products, int[] prices) Initializes the object with n, the discount, the products and their prices.
+ * double getBill(int[] product, int[] amount) returns the value of the bill and apply the discount if needed. Answers within 10^-5 of the actual value will be accepted as correct.
+ *
+ * Example 1:
+ * Input
+ * ["Cashier","getBill","getBill","getBill","getBill","getBill","getBill","getBill"]
+ * [[3,50,[1,2,3,4,5,6,7],[100,200,300,400,300,200,100]],[[1,2],[1,2]],[[3,7],[10,10]],[[1,2,3,4,5,6,7],[1,1,1,1,1,1,1]],[[4],[10]],[[7,3],[10,10]],[[7,5,3,1,6,4,2],[10,10,10,9,9,9,7]],[[2,3,5],[5,3,2]]]
+ * Output
+ * [null,500.0,4000.0,800.0,4000.0,4000.0,7350.0,2500.0]
+ * Explanation
+ * Cashier cashier = new Cashier(3,50,[1,2,3,4,5,6,7],[100,200,300,400,300,200,100]);
+ * cashier.getBill([1,2],[1,2]);                        // return 500.0, bill = 1 * 100 + 2 * 200 = 500.
+ * cashier.getBill([3,7],[10,10]);                      // return 4000.0
+ * cashier.getBill([1,2,3,4,5,6,7],[1,1,1,1,1,1,1]);    // return 800.0, The bill was 1600.0 but as this is the third customer, he has a discount of 50% which means his bill is only 1600 - 1600 * (50 / 100) = 800.
+ * cashier.getBill([4],[10]);                           // return 4000.0
+ * cashier.getBill([7,3],[10,10]);                      // return 4000.0
+ * cashier.getBill([7,5,3,1,6,4,2],[10,10,10,9,9,9,7]); // return 7350.0, Bill was 14700.0 but as the system counted three more customers, he will have a 50% discount and the bill becomes 7350.0
+ * cashier.getBill([2,3,5],[5,3,2]);                    // return 2500.0
+ *
+ *
+ * Constraints:
+ * 1 <= n <= 10^4
+ * 0 <= discount <= 100
+ * 1 <= products.length <= 200
+ * 1 <= products[i] <= 200
+ * There are not repeated elements in the array products.
+ * prices.length == products.length
+ * 1 <= prices[i] <= 1000
+ * 1 <= product.length <= products.length
+ * product[i] exists in products.
+ * amount.length == product.length
+ * 1 <= amount[i] <= 1000
+ * At most 1000 calls will be made to getBill.
+ * Answers within 10^-5 of the actual value will be accepted as correct.
+ * */
+public class _1357 {
+    public static class Solution1 {
+        public static class Cashier {
+
+            int customerCount;
+            int n;
+            Map<Integer, Integer> productsToPrices;
+            int discount;
+
+            public Cashier(int n, int discount, int[] products, int[] prices) {
+                this.n = n;
+                this.customerCount = 0;
+                this.discount = discount;
+                this.productsToPrices = new HashMap<>();
+                for (int i = 0; i < products.length; i++) {
+                    productsToPrices.put(products[i], prices[i]);
+                }
+            }
+
+            public double getBill(int[] product, int[] amount) {
+                double totalPrice = 0;
+                for (int i = 0; i < product.length; i++) {
+                    totalPrice += productsToPrices.get(product[i]) * amount[i];
+                }
+                if (customerCount + 1 == n) {
+                    //apply discount
+                    totalPrice *= (double) (100 - discount) / 100;
+                    customerCount = 0;
+                } else {
+                    customerCount++;
+                }
+                return totalPrice;
+            }
+        }
+    }
+}
diff --git a/src/test/java/com/fishercoder/_1357Test.java b/src/test/java/com/fishercoder/_1357Test.java
@@ -0,0 +1,22 @@
+package com.fishercoder;
+
+import com.fishercoder.solutions._1357;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class _1357Test {
+    private static _1357.Solution1.Cashier cashier;
+
+    @Test
+    public void test1() {
+        cashier = new _1357.Solution1.Cashier(3, 50, new int[]{1, 2, 3, 4, 5, 6, 7}, new int[]{100, 200, 300, 400, 300, 200, 100});
+        assertEquals(500.0, cashier.getBill(new int[]{1, 2}, new int[]{1, 2}), 0);
+        assertEquals(4000.0, cashier.getBill(new int[]{3, 7}, new int[]{10, 10}), 0);
+        assertEquals(800.0, cashier.getBill(new int[]{1, 2, 3, 4, 5, 6, 7}, new int[]{1, 1, 1, 1, 1, 1, 1}), 0);
+        assertEquals(4000.0, cashier.getBill(new int[]{4}, new int[]{10}), 0);
+        assertEquals(4000.0, cashier.getBill(new int[]{7, 3}, new int[]{10, 10}), 0);
+        assertEquals(7350.0, cashier.getBill(new int[]{7, 5, 3, 1, 6, 4, 2}, new int[]{10, 10, 10, 9, 9, 9, 7}), 0);
+        assertEquals(2500.0, cashier.getBill(new int[]{2, 3, 5}, new int[]{5, 3, 2}), 0);
+    }
+}
