Easy Recursive Python 7 lines Solution
Similar to #112 and #113, check the whole tree.\nThe only difference is: Any node can play as start or end in a valid path.\nAfter each visit, use current node 
Similar to #112 and #113, check the whole tree.\nThe only difference is: Any node can play as start or end in a valid path.\nAfter each visit, use current node as start, and update the "targets" list.\nPass the updated targets and initial target through.\n\nBase case:\n1. node is None\n\nRecursive case:\n1. node fits in certain path sum.\n2. node doesn't meet.\n\n```\nclass Solution(object):\n    def pathSum(self, root, s):\n        return self.helper(root, s, [s])\n\n    def helper(self, node, origin, targets):\n        if not node: return 0\n        hit = 0\n        for t in targets:\n            if not t-node.val: hit += 1                          # count if sum == target\n        targets = [t-node.val for t in targets]+[origin]         # update the targets\n        return hit+self.helper(node.left, origin, targets)+self.helper(node.right, origin, targets)\n```
['Python']