p

```
"""
Task:
Given an array of integers citations where citations[i] is the number of
citations a researcher received for their ith paper, return compute the
researcher's h-index.
According to the definition of h-index on Wikipedia: A scientist has an
index h if h of their n papers have at least h citations each, and the other
n - h papers have no more than h citations each.
If there are several possible values for h, the maximum one is taken as the
h-index.
H-Index link: https://en.wikipedia.org/wiki/H-index
Implementation notes:
Use sorting of array
Leetcode link: https://leetcode.com/problems/h-index/description/
n = len(citations)
Runtime Complexity: O(n * log(n))
Space Complexity: O(1)
"""
def h_index(citations: list[int]) -> int:
"""
Return H-index of citations
>>> h_index([3, 0, 6, 1, 5])
3
>>> h_index([1, 3, 1])
1
>>> h_index([1, 2, 3])
2
>>> h_index('test')
Traceback (most recent call last):
...
ValueError: The citations should be a list of non negative integers.
>>> h_index([1,2,'3'])
Traceback (most recent call last):
...
ValueError: The citations should be a list of non negative integers.
>>> h_index([1,2,-3])
Traceback (most recent call last):
...
ValueError: The citations should be a list of non negative integers.
"""
# validate:
if not isinstance(citations, list) or not all(
isinstance(item, int) and item >= 0 for item in citations
):
raise ValueError("The citations should be a list of non negative integers.")
citations.sort()
len_citations = len(citations)
for i in range(len_citations):
if citations[len_citations - 1 - i] <= i:
return i
return len_citations
if __name__ == "__main__":
import doctest
doctest.testmod()
```