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The k-digit number N is an Armstrong number if and only if the k-th power of each digit sums to N.
Given a positive integer N, return true if and only if it is an Armstrong number.
Example 1:
Input: 153
Output: true
Explanation:
153 is a 3-digit number, and 153 = 1^3 + 5^3 + 3^3.
Example 2:
Input: 123
Output: false
Explanation:
123 is a 3-digit number, and 123 != 1^3 + 2^3 + 3^3 = 36.
Note:
1 <= N <= 10^8
[Math]
Hint 1
Check if the given k-digit number equals the sum of the k-th power of it's digits.
Hint 2
How to compute the sum of the k-th power of the digits of a number ? Can you divide the number into digits using division and modulus operations ?
Hint 3
You can find the least significant digit of a number by taking it modulus 10. And you can remove it by dividing the number by 10 (integer division). Once you have a digit, you can raise it to the power of k and add it to the sum.