# 209. Minimum Size Subarray Sum

## Medium

***

Given an array of positive integers `nums` and a positive integer `target`, return the minimal length of a **contiguous subarray** `[numsl, numsl+1, ..., numsr-1, numsr]` of which the sum is greater than or equal to `target`. If there is no such subarray, return `0` instead.

**Example 1:**

```
Input: target = 7, nums = [2,3,1,2,4,3]
Output: 2
Explanation: The subarray [4,3] has the minimal length under the problem constraint.
```

**Example 2:**

```
Input: target = 4, nums = [1,4,4]
Output: 1
```

**Example 3:**

```
Input: target = 11, nums = [1,1,1,1,1,1,1,1]
Output: 0
```

**Constraints:**

* `1 <= target <= 109`
* `1 <= nums.length <= 105`
* `1 <= nums[i] <= 105`

**Follow up:** If you have figured out the `O(n)` solution, try coding another solution of which the time complexity is `O(n log(n))`.

```python
class Solution:
    def minSubArrayLen(self, target: int, nums: List[int]) -> int:
        start = index = 0
        total = 0
        result = len(nums)*2 # Dummy Value
        while index < len(nums):
            total += nums[index]
            while total >= target and start < len(nums):
                result = min(result, (index-start+1))
                total -= nums[start]
                start+=1
            index += 1
        return 0 if result == len(nums)*2 else result
```