給定一個二叉樹,返回所有從根節點到葉子節點的路徑。
說明: 葉子節點是指沒有子節點的節點。
示例:
輸入:
1
/ \
2 3
\
5
輸出: ["1->2->5", "1->3"]
思路:遞歸,將當前節點的數字加在此節點的左子樹和右子樹上
# 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]:
result = list()
if root == None:
return result
if root.left == None and root.right == None:
result.append(str(root.val))
return result
leftStr = self.binaryTreePaths(root.left)
for s in leftStr:
result.append(str(root.val) + '->' + str(s))
rightStr = self.binaryTreePaths(root.right)
for s in rightStr:
result.append(str(root.val) + '->' + str(s))
return result