```
class Solution(object):
def summaryRanges(self, nums):
"""
:type nums: List[int]
:rtype: List[str]
"""
n = len(nums); ans = []
begin = 0; end = 0
if n == 1: return [str(nums[0])]; tmp = ''
while end <= n-1:
while end < n-1 and nums[end]+1 == nums[end+1]:
end += 1
if begin == end:
tmp = str(nums[begin])
else:
tmp = str(nums[begin]) + '->' + str(nums[end])
ans.append(tmp)
begin = end + 1
end = begin
return ans
```