leetcode-bt

257. Binary Tree Paths.py

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution:
    def binaryTreePaths(self, root: TreeNode) -> List[str]:
        res = []
        def dfs(root, path = []):
            if root:
                if not root.right and not root.left:
                    res.append(path + [root.val])
                dfs(root.left, path + [root.val])
                dfs(root.right, path + [root.val])
        dfs(root,[])
        return ["->".join([str(n) for n in path]) for path in res]       
    
    def binaryTreePaths(self, root: TreeNode) -> List[str]:
        if not root:
            return []
        all_paths = []
        def dfs(r, path = []):
            if not r:
                return 
            if not r.left and not r.right:
                all_paths.append(path+[r.val])
                
            dfs(r.left, path + [r.val])
            dfs(r.right, path + [r.val])
            
        dfs(root, [])
        return ["->".join([str(n) for n in path]) for path in all_paths]