solves calculate money in leetcode bank

Author: anishLearnsToCode

README.md

@@ -421,7 +421,7 @@
 | 1704 | [Determine if String Halves Are Alike](https://leetcode.com/problems/determine-if-string-halves-are-alike)                                                |                                                         [![Java](assets/java.png)](src/DetermineIfStringHalvesAreAlike.java)                                                         |                                                                                                                                   |
 | 1708 | 🔒 [Largest Subarray Length K](https://leetcode.com/problems/largest-subarray-length-k/)                                                                  |                                                                                                                                                                                      |                                                                                                                                   |
 | 1710 | [Maximum Units on a Truck](https://leetcode.com/problems/maximum-units-on-a-truck/)                                                                       |                                                              [![Java](assets/java.png)](src/MaximumUnitsOnATruck.java)                                                               |                                                                                                                                   |
-| 1716 | [Calculate Money in Leetcode Bank](https://leetcode.com/problems/calculate-money-in-leetcode-bank)                                                        |                                                                                                                                                                                      |                                                                                                                                   |
+| 1716 | [Calculate Money in Leetcode Bank](https://leetcode.com/problems/calculate-money-in-leetcode-bank)                                                        |                                                          [![Java](assets/java.png)](src/CalculateMoneyInLeetCodeBank.java)                                                           |                                                                                                                                   |
 | 1720 | [Decode XORed Array](https://leetcode.com/problems/decode-xored-array)                                                                                    |                                                                                                                                                                                      |                                                                                                                                   |
 | 1725 | [Number Of Rectangles That Can Form The Largest Square](https://leetcode.com/problems/number-of-rectangles-that-can-form-the-largest-square)              |                                                                                                                                                                                      |                                                                                                                                   |
 | 1732 | [Find the Highest Altitude](https://leetcode.com/problems/find-the-highest-altitude)                                                                      |                                                                                                                                                                                      |                                                                                                                                   |

src/CalculateMoneyInLeetCodeBank.java

@@ -0,0 +1,19 @@
+public class CalculateMoneyInLeetCodeBank {
+    private static final int SUM_7 = 28;
+
+    public int totalMoney (int n) {
+        final int r = ceil((double) n / 7);
+        return r * SUM_7
+                + 7 * summation(r - 1)
+                - (summation(6 + r) - summation(n % 7 == 0 ? 6 + r : r - 1 + n % 7));
+    }
+
+    private int ceil(double d) {
+        return (int) Math.ceil(d);
+    }
+
+    private int summation(int x) {
+        if (x <= 0) return 0;
+        return (x * (x + 1)) / 2;
+    }
+}