Check for an Armstrong Number

📌 Definition:

📖 Detailed Explanation:

Count the digits d, then sum each digit raised to the power d and compare to the original number. Extract digits with %10 and /10. O(number of digits) plus the power computations.

💻 Solutions:

• Java
• JavaScript
• Python

public static boolean isArmstrong(int n) {
    int digits = String.valueOf(n).length();
    int sum = 0, temp = n;
    while (temp != 0) {
        int d = temp % 10;
        sum += (int) Math.pow(d, digits);
        temp /= 10;
    }
    return sum == n;
}

function isArmstrong(n) {
  const digits = String(n).length;
  const sum = String(n).split('')
    .reduce((acc, d) => acc + Math.pow(Number(d), digits), 0);
  return sum === n;
}

def is_armstrong(n):
    digits = len(str(n))
    return n == sum(int(d) ** digits for d in str(n))

🔑 Key Points:

• Raise each digit to the power of the digit COUNT
• Compare the sum to the original
• Works for any digit length, not just 3
• O(digits)

🌍 Real-World Example: