题目链接

https://leetcode.cn/problems/binary-tree-paths/

代码

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution:
    def traversal(self, node, result, path):
        path.append(node.val)
        if not node.left and not node.right:
            spath = '->'.join(map(str, path))
            result.append(spath)
            return
        if node.left:
            self.traversal(node.left, result, path)
            path.pop()
        if node.right:
            self.traversal(node.right, result, path)
            path.pop()

    def binaryTreePaths(self, root: Optional[TreeNode]) -> List[str]:
        result = []
        path = []
        if not root:
            return None
        self.traversal(root, result, path)
        return result

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution:
    def traversal(self, node, result, path):
        path += str(node.val)
        if not node.left and not node.right:
            result.append(path)
            return
        if node.left:
            self.traversal(node.left, result, path + '->')
        if node.right:
            self.traversal(node.right, result, path + '->')

    def binaryTreePaths(self, root: Optional[TreeNode]) -> List[str]:
        result = []
        path = ''
        if not root:
            return None
        self.traversal(root, result, path)
        return result