Minimum Size Subarray Sum

class Solution:
    def minSubArrayLen(self, target, nums):
        csum = 0
        cmin = float('inf')
        lx = 0
        for rx, n in enumerate(nums):
            csum = csum + n
            while csum >= target:
                cmin = min(cmin, rx - lx + 1)
                csum = csum - nums[lx]
                lx = lx + 1
        return cmin if cmin != float('inf') else 0