Change project structure to a Maven Java project + Refactor (#2816)

src/main/java/com/thealgorithms/dynamicprogramming/CoinChange.java

@@ -0,0 +1,85 @@
+package com.thealgorithms.dynamicprogramming;
+
+/**
+ * @author Varun Upadhyay (https://github.com/varunu28)
+ */
+public class CoinChange {
+
+    // Driver Program
+    public static void main(String[] args) {
+
+        int amount = 12;
+        int[] coins = {2, 4, 5};
+
+        System.out.println(
+                "Number of combinations of getting change for " + amount + " is: " + change(coins, amount));
+        System.out.println(
+                "Minimum number of coins required for amount :"
+                + amount
+                + " is: "
+                + minimumCoins(coins, amount));
+    }
+
+    /**
+     * This method finds the number of combinations of getting change for a
+     * given amount and change coins
+     *
+     * @param coins The list of coins
+     * @param amount The amount for which we need to find the change Finds the
+     * number of combinations of change
+     */
+    public static int change(int[] coins, int amount) {
+
+        int[] combinations = new int[amount + 1];
+        combinations[0] = 1;
+
+        for (int coin : coins) {
+            for (int i = coin; i < amount + 1; i++) {
+                combinations[i] += combinations[i - coin];
+            }
+            // Uncomment the below line to see the state of combinations for each coin
+            // printAmount(combinations);
+        }
+
+        return combinations[amount];
+    }
+
+    /**
+     * This method finds the minimum number of coins needed for a given amount.
+     *
+     * @param coins The list of coins
+     * @param amount The amount for which we need to find the minimum number of
+     * coins. Finds the the minimum number of coins that make a given value.
+     */
+    public static int minimumCoins(int[] coins, int amount) {
+        // minimumCoins[i] will store the minimum coins needed for amount i
+        int[] minimumCoins = new int[amount + 1];
+
+        minimumCoins[0] = 0;
+
+        for (int i = 1; i <= amount; i++) {
+            minimumCoins[i] = Integer.MAX_VALUE;
+        }
+        for (int i = 1; i <= amount; i++) {
+            for (int coin : coins) {
+                if (coin <= i) {
+                    int sub_res = minimumCoins[i - coin];
+                    if (sub_res != Integer.MAX_VALUE && sub_res + 1 < minimumCoins[i]) {
+                        minimumCoins[i] = sub_res + 1;
+                    }
+                }
+            }
+        }
+        // Uncomment the below line to see the state of combinations for each coin
+        // printAmount(minimumCoins);
+        return minimumCoins[amount];
+    }
+
+    // A basic print method which prints all the contents of the array
+    public static void printAmount(int[] arr) {
+        for (int i = 0; i < arr.length; i++) {
+            System.out.print(arr[i] + " ");
+        }
+        System.out.println();
+    }
+}