In short, I suppose the possible value of h from 1 to n, the total number of the paper list. In the inner for loop, go through all the index and count the paper which has the larger citation number than h. After all, report the max h which meet the requirement.

```
def hIndex(self, citations):
"""
:type citations: List[int]
:rtype: int
"""
n=len(citations)
result=0
citations.sort()
for h in range(1,n+1):
count=0
for i in range(n):
if citations[i]>=h:
count+=1
if count>=h:
result=max(h,result)
return result
```