Likou 112, 113 path sum I, II

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None
# 112
class Solution:
    def hasPathSum(self, root: TreeNode, sum: int) -> bool:
        if root is None:
            return False
        # 前序遍历
        self.flag = False
        def PreOrder(root, count):
            if root.left is None and root.right is None:
                if count == sum:
                    # print(count)
                    self.flag = True
            
            # left
            if root.left:
                PreOrder(root.left, count+root.left.val)
            if root.right:
                PreOrder(root.right, count+root.right.val)    
            return self.flag
        
        return PreOrder(root, root.val)

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None
# 113
class Solution:
    def pathSum(self, root: TreeNode, sum: int) -> List[List[int]]:
        if root is None:
            return []
        # 前序遍历
        self.new_tree = []
        def PreOrder(root, count, path):
            if root.left is None and root.right is None:
                if count == sum:
                    self.new_tree.append(path)
            if root.left:
                path_l = path[:]	#复制列表，很关键
                path_l.append(root.left.val)
                PreOrder(root.left, count+root.left.val, path_l)
            if root.right:
                path_r = path[:]
                path_r.append(root.right.val)
                PreOrder(root.right, count+root.right.val, path_r) 
            return self.flag
        PreOrder(root, root.val, [root.val])
        return self.new_tree