Find the maximum and minimum in an array

Summary

Return both the minimum and maximum values from an array.

Problem statement

Given a list of comparable values (integers), return a tuple (minimum, maximum). If the list is empty, return (None, None). You should traverse the list only once (O(n) time) and O(1) extra space.

Task

Implement a function that scans an array once to determine both min and max values, handling single-element and empty arrays explicitly.

Examples

Input format

A single argument: a list of integers, e.g. [3, 1, 4].

Output format

A tuple (min_value, max_value). For an empty list return (None, None).

Constraints

List length 0..10^6. Values are integers. Time O(n), space O(1).

Samples