Multiplicative Persistence

ardallie · ardallie · commit 7038c816dea7 · 2021-08-14T13:04:05.000+01:00
diff --git a/src/easy/MultiplicativePersistence.java b/src/easy/MultiplicativePersistence.java
@@ -0,0 +1,48 @@
+package easy;
+
+/**
+ * Have the function MultiplicativePersistence(num) take the num parameter being passed
+ * which will always be a positive integer
+ * and return its multiplicative persistence which is
+ * the number of times you must multiply the digits in num until you reach a single digit.
+ * ---
+ * For example: if num is 39 then your program
+ * should return 3 because 3 * 9 = 27 then 2 * 7 = 14
+ * and finally 1 * 4 = 4 then you stop at 4.
+ */
+public class MultiplicativePersistence {
+
+  /**
+   * Multiplicative Persistence function.
+   *
+   * @param num input number
+   * @return the number of times you must multiply
+   */
+  private static int multiplicativePersistence(int num) {
+    int times = 0;
+    int multiplied = num;
+    while (multiplied > 9) {
+      int product = 1;
+      String[] intArr = Integer.toString(multiplied).split("");
+      for (String i : intArr) {
+        product *= Integer.parseInt(i);
+      }
+      multiplied = product;
+      times++;
+    }
+    return times;
+  }
+
+  /**
+   * Entry point.
+   *
+   * @param args command line arguments
+   */
+  public static void main(String[] args) {
+    var result1 = multiplicativePersistence(2677889);
+    System.out.println(result1);
+    var result2 = multiplicativePersistence(8192);
+    System.out.println(result2);
+  }
+
+}
