What is the optimal time complexity of solving Find Second Smallest Element in an Array?

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 Find Second Smallest Element in an Array?

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 Find Second Smallest Element in an Array?

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 Find Second Smallest Element in an Array?

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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Find Second Smallest Element in an Array

Learn how to solve the 'Find Second Smallest Element in an Array' problem. This detailed resource details brute force and optimized approaches.

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Problem Statement

Easy

Write a function second_smallest(arr) that takes a list of integers arr and returns the second smallest distinct element. If no second smallest exists (all elements are the same or array has fewer than 2 distinct values), return -1.

Constraints

•1 <= len(arr) <= 10^5
•-10^9 <= arr[i] <= 10^9

Examples

Example 1

Input

arr = [3, 1, 4, 1, 5]

Output

Explanation

Sorted distinct values: [1, 3, 4, 5]. The second smallest is 3.

Example 2

Input

arr = [5, 5, 5]

Output

-1

Explanation

All elements are the same. No second smallest exists.

Example 3

Input

arr = [10, 20]

Output

Explanation

Two distinct values: 10, 20. Second smallest is 20.

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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