Calculate the number of ways of representing n cents

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.

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));
+
+    }
+}