Given an integer array `nums`

, find the contiguous subarray (containing at least one number) which has the largest sum and return its sum.

**Example**:

Input: [-2,1,-3,4,-1,2,1,-5,4]

Output: 6

Explanation: [4,-1,2,1] has the largest sum = 6.

**Follow up**:

If you have figured out the O(*n*) solution, try coding another solution using the divide and conquer approach, which is more subtle.

## Solution

```
import sys
from typing import List
class Solution:
def maxSubArray(self, nums: List[int]) -> int:
maxSum = -sys.maxsize-1
curSum = -sys.maxsize-1
for i in range(len(nums)):
curSum = max(nums[i], curSum + nums[i])
maxSum = max(curSum, maxSum)
return maxSum
```

## Test Cases

```
test = Solution()
answer = test.maxSubArray([-2,1,-3,4,-1,2,1,-5,4])
assert answer == 6
answer = test.maxSubArray([-2])
assert answer == -2
answer = test.maxSubArray([-2,-3])
assert answer == -2
print('All Passed!')
```

## Big O Analysis

**Space Complexity**: O(1)

**Time Complexity**: O(N)