Added PowerOfFour algorithm in bitmanipulation

src/main/java/com/thealgorithms/bitmanipulation/PowerOfFour.java

@@ -0,0 +1,26 @@
+package com.thealgorithms.bitmanipulation;
+
+/**
+ * This class provides a method to check if a given number is a power of four.
+ */
+public final class PowerOfFour {
+
+    /** Private constructor to prevent instantiation. */
+    private PowerOfFour() {
+        throw new AssertionError("Cannot instantiate utility class.");
+    }
+
+    /**
+     * Checks whether the given integer is a power of four.
+     *
+     * @param n the number to check
+     * @return true if n is a power of four, false otherwise
+     */
+    public static boolean isPowerOfFour(int n) {
+        if (n <= 0) {
+            return false;
+        } else {
+            return (n & (n - 1)) == 0 && (n & 0x55555555) != 0;
+        }
+    }
+}

src/test/java/com/thealgorithms/bitmanipulation/PowerOfFour.java

@@ -0,0 +1,26 @@
+package com.thealgorithms.bitmanipulation;
+
+/**
+ * This class provides a method to check if a given number is a power of four.
+ */
+public final class PowerOfFour {
+
+    // Private constructor to prevent instantiation
+    private PowerOfFour() {
+        throw new AssertionError("Cannot instantiate utility class");
+    }
+
+    /**
+     * Checks whether the given integer is a power of four.
+     *
+     * @param n the number to check
+     * @return true if n is a power of four, false otherwise
+     */
+    public static boolean isPowerOfFour(int n) {
+        if (n <= 0) {
+            return false;
+        } else {
+            return (n & (n - 1)) == 0 && (n & 0x55555555) != 0;
+        }
+    }
+}

src/test/java/com/thealgorithms/bitmanipulation/PowerOfFourTest.java

@@ -0,0 +1,32 @@
+package com.thealgorithms.bitmanipulation;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for {@link PowerOfFour}.
+ */
+public final class PowerOfFourTest {
+
+    @Test
+    void testPowerOfFourTrueCases() {
+        Assertions.assertTrue(PowerOfFour.isPowerOfFour(1));
+        Assertions.assertTrue(PowerOfFour.isPowerOfFour(4));
+        Assertions.assertTrue(PowerOfFour.isPowerOfFour(16));
+        Assertions.assertTrue(PowerOfFour.isPowerOfFour(64));
+    }
+
+    @Test
+    void testPowerOfFourFalseCases() {
+        Assertions.assertFalse(PowerOfFour.isPowerOfFour(0));
+        Assertions.assertFalse(PowerOfFour.isPowerOfFour(2));
+        Assertions.assertFalse(PowerOfFour.isPowerOfFour(8));
+        Assertions.assertFalse(PowerOfFour.isPowerOfFour(12));
+    }
+
+    @Test
+    void testNegativeNumbers() {
+        Assertions.assertFalse(PowerOfFour.isPowerOfFour(-4));
+        Assertions.assertFalse(PowerOfFour.isPowerOfFour(-16));
+    }
+}