added algo for checking the number is power of four or not (TheAlgorithms#1360)

dev-madhurendra · madhuredra · web-flow · commit 4fe8a67ea617 · 2023-09-22T14:51:29.000+05:30
* added algo for checking the number is power of four or not

* Update IsPowerofFour.js

* Update IsPowerofFour.js

* fix code style

* used proper JSDoc comment and fixed test issues

* fixed test case issue

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Co-authored-by: madhuredra &lt;madhuredra.tiwari@zemosolabs.com&gt;
diff --git a/Bit-Manipulation/IsPowerofFour.js b/Bit-Manipulation/IsPowerofFour.js
@@ -0,0 +1,17 @@
+/**
+ * @author : dev-madhurendra
+ * Checks whether the given number is a power of four or not.
+ *
+ * A number is considered a power of four if and only if there is a single '1' bit in its binary representation,
+ * and that '1' bit is at the first position, followed by an even number of '0' bits.
+ *
+ * @param {number} n - The input number to check.
+ * @returns {boolean} True if the number is a power of four, false otherwise.
+ *
+ * @example
+ * const result = isPowerOfFour(16); // Returns true (16 is 4^2)
+ * const result2 = isPowerOfFour(5);  // Returns false (5 is not a power of four)
+ */
+const isPowerOfFour = (n) => ((n > 0) && ((n & n - 1) === 0) && (n % 3 === 1))
+
+export { isPowerOfFour }
diff --git a/Bit-Manipulation/test/IsPowerOfFour.test.js b/Bit-Manipulation/test/IsPowerOfFour.test.js
@@ -0,0 +1,14 @@
+import { isPowerOfFour } from '../IsPowerofFour'
+
+describe('IsPowerOfFour', () => {
+  it.each([
+    [0, false],
+    [4, true],
+    [16, true],
+    [12, false],
+    [64, true],
+    [-64, false]
+  ])('should return the number is power of four or not', (n, expected) => {
+    expect(isPowerOfFour(n)).toBe(expected)
+  })
+})
