```
class Solution(object):
def findKthLargest(self, nums, k):
"""
:type nums: List[int]
:type k: int
:rtype: int
"""
s, e = 0, len(nums)-1
while s <= e:
rand = random.randint(s, e)
nums[rand], nums[e] = nums[e], nums[rand]
i = s
for j in range(s, e):
if nums[j] > nums[e]:
nums[i], nums[j] = nums[j], nums[i]
i+=1
nums[i], nums[e] = nums[e], nums[i]
if i == k-1:
return nums[i]
elif i < k-1:
s = i+1
k-=(i-s+1)
else:
e = i-1
return -1
```