```
class Solution(object):
def lengthOfLIS(self, nums):
"""
:type nums: List[int]
:rtype: int
"""
if not nums:
return 0
stack = [nums[0]]
maxLen = 1
for i in range(1, len(nums)):
if nums[i] > stack[-1]:
stack.append(nums[i])
else:
index = self.binarySearch(stack, nums[i])
stack[index] = nums[i]
maxLen = max(maxLen, len(stack))
return maxLen
def binarySearch(self, stack, num):
left, right = 0, len(stack)-1
while left < right:
mid = left + (right - left) / 2
if stack[mid] >= num:
right = mid
else:
left = mid + 1
return left
```