What is the optimal time complexity of solving Armstrong number?

The optimized solution achieves a time complexity of O(n) by using sorting, mathematical shortcuts, or hash table lookups.

What is the auxiliary space complexity for Armstrong number?

The space complexity is O(1) since we only use a minimal/constant amount of extra memory for tracking variables (or auxiliary space if dynamic structures are allocated).

What are the typical edge cases we must handle in Armstrong number?

Key edge cases include empty collections, negative or large bounds causing integer overflow, arrays with only one element, or inputs where target criteria are not met.

How can we optimize the brute force approach for Armstrong number?

Brute force methods often inspect all possible combinations. We optimize this by sorting the input list to enable binary search, or tracking processed items in a set to avoid redundant nested loop lookups.

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Python BasicsEasy

Armstrong number

Learn how to solve the 'Armstrong number' problem. This detailed resource details brute force and optimized approaches.

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Problem Statement

Easy

Write a function is_armstrong(n) that takes a positive integer n and returns True if it is an Armstrong number, or False otherwise. An Armstrong number (narcissistic number) is a number that equals the sum of its own digits each raised to the power of the number of digits. For example, 153 has 3 digits and 1^3 + 5^3 + 3^3 = 153.

Constraints

•1 <= n <= 10^6

Examples

Example 1

Input

n = 153

Output

True

Explanation

153 has 3 digits. 1^3 + 5^3 + 3^3 = 1 + 125 + 27 = 153. So it is an Armstrong number.

Example 2

Input

n = 370

Output

True

Explanation

370 has 3 digits. 3^3 + 7^3 + 0^3 = 27 + 343 + 0 = 370.

Example 3

Input

n = 123

Output

False

Explanation

123 has 3 digits. 1^3 + 2^3 + 3^3 = 1 + 8 + 27 = 36, which is not 123.

Need a Hint?

Use simple arithmetic operators (like modulo `%`, division `//`), conditional checks, or loops to inspect number properties.

Edge Cases to Watch

Empty list or null input variables
Single item lists/arrays
Extremely large input bounds causing integer or stack overflow

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