What is the optimal time complexity of solving Reversing a Number using Recursion?

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 Reversing a Number using Recursion?

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 Reversing a Number using Recursion?

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 Reversing a Number using Recursion?

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 BasicsMedium

Reversing a Number using Recursion

Learn how to solve the 'Reversing a Number using Recursion' problem. This detailed resource details brute force and optimized approaches.

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Problem Statement

Medium

Write a function reverse_number(n) that reverses the digits of a given non-negative integer n using recursion and returns the reversed number as an integer. For example, 1234 becomes 4321. Leading zeros in the reversed result should be dropped (e.g., 1200 reversed is 21).

Constraints

•0 <= n <= 10^9

Examples

Example 1

Input

n = 1234

Output

Explanation

The digits 1, 2, 3, 4 are reversed to 4, 3, 2, 1 giving 4321.

Example 2

Input

n = 1200

Output

Explanation

Reversed digits are 0, 0, 2, 1. Leading zeros are dropped, giving 21.

Example 3

Input

n = 5

Output

Explanation

A single digit number reversed is itself.

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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