Check if a Number is a Power of Two

📌 Definition:

📖 Detailed Explanation:

A power of two has exactly one set bit, so n & (n - 1) == 0 for positive n. Guard n > 0 (zero and negatives are not powers of two). This is O(1) and far slicker than dividing by 2 in a loop.

💻 Solutions:

• Java
• JavaScript
• Python

public static boolean isPowerOfTwo(int n) {
    return n > 0 && (n & (n - 1)) == 0;
}

function isPowerOfTwo(n) {
  return n > 0 && (n & (n - 1)) === 0;
}

def is_power_of_two(n):
    return n > 0 and (n & (n - 1)) == 0

🔑 Key Points:

• A power of two has exactly one set bit
• n > 0 && (n & (n-1)) == 0
• O(1) bit trick beats the divide loop
• Guard zero and negatives

🌍 Real-World Example: