递归与二叉树_leetcode112

class Solution(object):
    def hasPathSum(self, root, sum):
        """
        :type root: TreeNode
        :type sum: int
        :rtype: bool
        """
        if not root:
            return False

        if root and not root.left and not root.right:
            return sum == root.val
        if self.hasPathSum(root.left,sum-root.val):
            return True
        if self.hasPathSum(root.right,sum-root.val):
            return True
        return False