257. Binary Tree Paths Easy

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Share Given a binary tree, return all root-to-leaf paths.

Note: A leaf is a node with no children.

Example:

Input:

1 /

Output: ["1->2->5", "1->3"]

Explanation: All root-to-leaf paths are: 1->2->5, 1->3

思路：dfs 记录每条线的数组 代码：python3

class Solution:    def binaryTreePaths(self, root: TreeNode) -> List[str]:        if not root: return []        arr=[]        def dfs(root,ar):            subAr=ar[:]            if not root:return            if not root.left and not root.right:                subAr.append(str(root.val))                arr.append(subAr)            else:                subAr.append(str(root.val))                            dfs(root.left,subAr)                dfs(root.right,subAr)                        dfs(root,[])        result=[]        for a in arr:            result.append('->'.join(a))        return result复制代码