From ccb2236899b5b8da1d215f47a5fbb9561225c900 Mon Sep 17 00:00:00 2001
From: Bogdan Popov <bogdan.popov@mail.ru>
Date: Thu, 20 Oct 2016 14:17:04 +0300
Subject: [PATCH] Coins exchange solution added

---
 README.md                            |  1 +
 src/TechInterview/CoinsExchange.java | 44 ++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+)
 create mode 100644 src/TechInterview/CoinsExchange.java

diff --git a/README.md b/README.md
index 190896d..522fe00 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,5 @@
 # README
+
 <img src="https://s-media-cache-ak0.pinimg.com/564x/2d/8e/e8/2d8ee815146390d567706f2c7b5c2916.jpg" width="300">
 
 This is a repo consisting of algorithms and data structures that I've implemented in Java.
diff --git a/src/TechInterview/CoinsExchange.java b/src/TechInterview/CoinsExchange.java
new file mode 100644
index 0000000..445031f
--- /dev/null
+++ b/src/TechInterview/CoinsExchange.java
@@ -0,0 +1,44 @@
+package TechInterview;
+
+public class CoinsExchange {
+
+    /**
+     * Given an in infinite number of quarters (25 cents), dimes (10 cents), nickels (5 cents) and pennies (1 cent),
+     * write code to calculate the number of ways of representing n cents.
+     */
+
+    static int changeCoins(int n) {
+        return changeCoinsWithCount(n, 4);
+    }
+
+    static int changeCoinsWithCount(int amount, int countOfcoins) {
+
+        if (amount == 0)
+            return 1;
+        if (amount < 0 || countOfcoins == 0)
+            return 0;
+        else
+            return changeCoinsWithCount(amount, countOfcoins - 1) + changeCoinsWithCount(amount - firstDenomination(countOfcoins), countOfcoins);
+    }
+
+    static int firstDenomination(int countOfCoins) {
+        switch (countOfCoins) {
+            case 1:
+                return 1;
+            case 2:
+                return 5;
+            case 3:
+                return 10;
+            case 4:
+                return 25;
+            default:
+                return 0;
+        }
+    }
+
+    public static void main(String[] args) {
+
+        System.out.println(changeCoins(100));
+
+    }
+}
\ No newline at end of file