Eulers hcf algorithm

src/main/java/com/thealgorithms/maths/EulerHCF.java

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+package com.thealgorithms.maths;
+
+/**
+ * Eulers HCF (Highest Common Factor) Algorithm
+ * Also known as Euclid's algorithm for finding the Greatest Common Divisor (GCD)
+ */
+public final class EulerHCF {
+    private EulerHCF() {
+    }
+
+    /**
+     * String of IllegalArgumentException for positive numbers
+     */
+    private static final String POSITIVE_NUMBERS = "Both numbers must be greater than 0";
+
+    /**
+     * Calculate the Highest Common Factor (HCF) of two numbers using Eulers algorithm.
+     * This is also known as the Greatest Common Divisor (GCD).
+     *
+     * @param num1 first number
+     * @param num2 second number
+     * @return the highest common factor of the two given numbers
+     */
+    public static int eulerHCF(final int num1, final int num2) {
+        if (num1 <= 0 || num2 <= 0) {
+            throw new IllegalArgumentException(POSITIVE_NUMBERS);
+        }
+        return eulerHCFHelper(num1, num2);
+    }
+
+    /**
+     * Helper method to recursively calculate HCF using Eulers algorithm.
+     *
+     * @param num1 first number
+     * @param num2 second number
+     * @return the highest common factor of the two given numbers
+     */
+    private static int eulerHCFHelper(final int num1, final int num2) {
+        if (num2 == 0) {
+            return num1;
+        }
+        return eulerHCFHelper(num2, num1 % num2);
+    }
+
+    /**
+     * Calculate the Highest Common Factor (HCF) of two numbers using Eulers algorithm (iterative approach).
+     *
+     * @param num1 first number
+     * @param num2 second number
+     * @return the highest common factor of the two given numbers
+     */
+    public static int eulerHCFIterative(final int num1, final int num2) {
+        if (num1 <= 0 || num2 <= 0) {
+            throw new IllegalArgumentException(POSITIVE_NUMBERS);
+        }
+        int a = num1;
+        int b = num2;
+        while (b != 0) {
+            int temp = b;
+            b = a % b;
+            a = temp;
+        }
+        return a;
+    }
+
+    /**
+     * Calculate the Highest Common Factor (HCF) of two long numbers using Eulers algorithm.
+     *
+     * @param num1 first long number
+     * @param num2 second long number
+     * @return the highest common factor of the two given numbers
+     */
+    public static long eulerHCF(final long num1, final long num2) {
+        if (num1 <= 0 || num2 <= 0) {
+            throw new IllegalArgumentException(POSITIVE_NUMBERS);
+        }
+        long a = num1;
+        long b = num2;
+        while (b != 0) {
+            long temp = b;
+            b = a % b;
+            a = temp;
+        }
+        return a;
+    }
+}