一道本來想用全局變量的題目
class Solution:
my_sum = 0
def convertBST(self, root: TreeNode) -> TreeNode:
global my_sum
if root is None:
return
self.convertBST(root.right)
print(root.val)
tmp = root.val
root.val += my_sum
my_sum += tmp
self.convertBST(root.left)
return root
錯誤:
NameError: name ‘my_sum’ is not defined
Line 18 in convertBST (Solution.py)
Line 14 in convertBST (Solution.py)
Line 48 in _driver (Solution.py)
Line 59 in (Solution.py)
fix: 類變量一定要使用 self
來引用之
# Definition for a binary tree node.
# class TreeNode:
# def __init__(self, x):
# self.val = x
# self.left = None
# self.right = None
class Solution:
my_sum = 0
def convertBST(self, root: TreeNode) -> TreeNode:
if root is None:
return
self.convertBST(root.right)
tmp = root.val
root.val += self.my_sum
self.my_sum += tmp
self.convertBST(root.left)
return root
'''
執行用時 :
132 ms
, 在所有 Python3 提交中擊敗了
16.13%
的用戶
內存消耗 :
15.9 MB
, 在所有 Python3 提交中擊敗了
5.44%
的用戶
'''