feat: added is power of two in bit manipulation (TheAlgorithms#157)

* feat : added is power of two in bit manipulation

* fix : file name fixed

---------

Co-authored-by: madhuredra <[email protected]>

Author: dev-madhurendra

bit_manipulation/is_power_of_2.ts

@@ -0,0 +1,25 @@
+/**
+ * This code will check whether the given number is a power of two or not.
+ * @author dev-madhurendra<https://github.com/dev-madhurendra>
+ * @explanation
+
+    A number will be a power of two if only one bit is set and rest are unset.
+    This is true for all the cases except 01 because (2^0 = 1) which is not a power of 2.
+    For eg: 10 (2^1 = 2), 100 (2^2 = 4), 10000 (2^4 = 16)
+
+    @see: https://www.hackerearth.com/practice/notes/round-a-number-to-the-next-power-of-2/
+
+    If we will subtract 1 from a number that is a power of 2 we will get it's 
+    1's complement.And we know that 1's complement is just opp. of that number.
+    So, (n & (n-1)) will be 0.
+
+    For eg:    (1000 & (1000-1))
+                1 0 0 0     // Original Number (8)
+                0 1 1 1     // After Subtracting 1 (8-1 = 7)
+                _______
+                0 0 0 0     // will become 0
+ * @param {number}
+ * @returns {boolean}
+ */
+
+export const isPowerOfTwo = (n: number): boolean => n > 0 && (n & (n - 1)) === 0

bit_manipulation/test/is_power_of_2.test.ts

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+import { isPowerOfTwo } from "../is_power_of_2"
+
+
+describe('IsPowerOfTwo' , () => {
+    it.each([
+        [0, false],
+        [1, true],
+        [4, true],
+        [1024, true],
+        [1025, false],
+      ])('Check if %i is a power of 2 or not', (number, expected) => {
+        expect(isPowerOfTwo(number)).toBe(expected);
+    });    
+})