leetcood学习笔记-113-路径总和 II

class Solution(object):
    def pathSum(self, root, sum):
        """
        :type root: TreeNode
        :type sum: int
        :rtype: List[List[int]]
        """
        r = []
        l = []
        if not root:
            return r
        def path(root, l , sum):
            if not root:
                return 
            l.append(root.val)
            if sum == root.val and not root.left and not root.right:
                r.append(list(l))#***此处为list(l) 若直接添加l,添加的是l的地址，l发生变化时，r中添加的值也发生变化

            path(root.left,l,sum-root.val)
            path(root.right,l,sum-root.val)
            l.pop()
        path(root,l,sum)
        return r