# Question

Given an array of citations (each citation is a non-negative integer) of a researcher, write a function to compute the researcher’s h-index.

According to the definition of h-index on Wikipedia: “A scientist has index h if h of his/her N papers have at least h citations each, and the other N − h papers have no more than h citations each.”

For example, given citations = [3, 0, 6, 1, 5], which means the researcher has 5 papers in total and each of them had received 3, 0, 6, 1, 5 citations respectively. Since the researcher has 3 papers with at least 3 citations each and the remaining two with no more than 3 citations each, his h-index is 3.

Note: If there are several possible values for h, the maximum one is taken as the h-index.

# Solution

class Solution(object):
def hIndex(self, citations):
"""
:type citations: List[int]
:rtype: int
"""
N = len(citations)
if (N == 0):
return 0
if (N == 1):
return min(1, citations[0])

citations.sort(reverse=True)

for h in range(1, N):
if(citations[h-1] >= h and citations[h] <= h):
return h
if(citations[N-1] >= N):
return N
else:
return 0