How do you identify Armstrong numbers programmatically?
This question asks for a number theory algorithm to check Armstrong properties. It tests digit extraction and power calculations.
Why Interviewers Ask This
Armstrong numbers are a classic problem to test mathematical logic and loop control. Interviewers want to see if candidates can extract digits, compute powers, and sum them correctly. It also checks handling of multi-digit numbers and edge cases.
How to Answer This Question
Explain extracting each digit using modulo and division. Raise each digit to the power of the total number of digits and sum them. Compare the sum to the original number. Discuss time complexity based on the number of digits.
Key Points to Cover
- Count digits
- Extract digits
- Power calculation
- Sum comparison
Sample Answer
An Armstrong number is one where the sum of its digits raised to the power of the count of digits equals the number itself. To check this, I first count the number of digits. Then, I iterate through each digit, raise it…
Common Mistakes to Avoid
- Using wrong power exponent
- Incorrect digit extraction logic
- Floating point precision errors
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