diff --git a/src/main/java/com/thealgorithms/maths/GenericRoot.java b/src/main/java/com/thealgorithms/maths/GenericRoot.java index 07f4756f93f8..e13efe5a77e0 100644 --- a/src/main/java/com/thealgorithms/maths/GenericRoot.java +++ b/src/main/java/com/thealgorithms/maths/GenericRoot.java @@ -1,30 +1,48 @@ package com.thealgorithms.maths; -/* - * Algorithm explanation: - * https://technotip.com/6774/c-program-to-find-generic-root-of-a-number/#:~:text=Generic%20Root%3A%20of%20a%20number,get%20a%20single%2Ddigit%20output.&text=For%20Example%3A%20If%20user%20input,%2B%204%20%2B%205%20%3D%2015. +/** + * Calculates the generic root (repeated digital sum) of a non-negative integer. + *
+ * For example, the generic root of 12345 is calculated as: + * 1 + 2 + 3 + 4 + 5 = 15, + * then 1 + 5 = 6, so the generic root is 6. + *
+ * Reference: + * https://technotip.com/6774/c-program-to-find-generic-root-of-a-number/ */ public final class GenericRoot { + + private static final int BASE = 10; + private GenericRoot() { } - private static int base = 10; - + /** + * Computes the sum of the digits of a non-negative integer in base 10. + * + * @param n non-negative integer + * @return sum of digits of {@code n} + */ private static int sumOfDigits(final int n) { assert n >= 0; - if (n < base) { + if (n < BASE) { return n; } - return n % base + sumOfDigits(n / base); + return (n % BASE) + sumOfDigits(n / BASE); } + /** + * Computes the generic root (repeated digital sum) of an integer. + * For negative inputs, the absolute value is used. + * + * @param n integer input + * @return generic root of {@code n} + */ public static int genericRoot(final int n) { - if (n < 0) { - return genericRoot(-n); - } - if (n > base) { - return genericRoot(sumOfDigits(n)); + int number = Math.abs(n); + if (number < BASE) { + return number; } - return n; + return genericRoot(sumOfDigits(number)); } }