Given an integer n, return true if it is a power of two. Otherwise, return false. An integer n is a power of two, if there exists an integer x such that n == 2x. Example 1: Input: n = 1 Output: true Explanation: 20 = 1 Example 2: Input: n = 16 Output: true Explanation: 24 = 16 Example 3: Input: n = 3 Output: false Example 4: Input: n = 4 Output: true Example 5: Input: n = 5 Output: false Constraints: -231 <= n <= 231 - 1 Follow up: Could you solve it without loops/recursion?