480. 二叉树的所有路径
给一棵二叉树,找出从根节点到叶子节点的所有路径。
Example
样例 1:
输入:{1,2,3,#,5}
输出:["1->2->5","1->3"]
解释:
1
/
2 3
5
样例 2:
输入:{1,2}
输出:["1->2"]
解释:
1
/
2
""" Definition of TreeNode: class TreeNode: def __init__(self, val): self.val = val self.left, self.right = None, None """ class Solution: """ @param root: the root of the binary tree @return: all root-to-leaf paths """ def binaryTreePaths(self, root): # write your code here path = [] result = [] self.dfs(root, path, result) return result def dfs(self, root, path, result): if not root: return path.append(str(root.val)) if root.left is None and root.right is None: result.append("->".join(path)) else: self.dfs(root.left, path, result) self.dfs(root.right, path, result) path.pop()
还有使用分治实现的,jiuzhang给的:
class Solution: """ @param root: the root of the binary tree @return: all root-to-leaf paths """ def binaryTreePaths(self, root): if root is None: return [] if root.left is None and root.right is None: return [str(root.val)] leftPaths = self.binaryTreePaths(root.left) rightPaths = self.binaryTreePaths(root.right) paths = [] for path in leftPaths + rightPaths: paths.append(str(root.val) + '->' + path) return paths