[FIXED] AttributeError: 'function' object has no attribute 'isSubtree' for recursive functions

Issue

I'm learning how to do binary tree functions in python, most of which are recursive, so I tried to run some leetcode solutions locally in my pycharm only to run into this error:

Traceback (most recent call last):
  File "LCPattern.py", line 55, in <module>
    a = Solution.isSubtree(self, t3,t4)
  File "LCPattern.py", line 39, in isSubtree
    return bool(s and t) and (is_the_same(s, t) or self.isSubtree(s.left, t) or self.isSubtree(s.right, t))
AttributeError: 'function' object has no attribute 'isSubtree'

code is

class Solution:
    def isSubtree(self, s: TreeNode, t: TreeNode) -> bool:

        def is_the_same(s, t):

            if not s and not t:
                # both s and t are empty
                return True

            elif s and t:
                # both s and t are non-empty
                # keep checking in DFS
                return s.val == t.val and is_the_same(s.left, t.left) and is_the_same(s.right, t.right)

            else:
                # one is empty, the other is non-empty
                return False

        # -----------------------------------------------------------
        return bool(s and t) and (is_the_same(s, t) or self.isSubtree(s.left, t) or self.isSubtree(s.right, t))

t3 = TreeNode(3)
t3.left = TreeNode(4)
t3.right = TreeNode(5)
t3.left.left = TreeNode(1)
t3.left.right = TreeNode(2)

t4 = TreeNode(4)
t4.left = TreeNode(1)
t4.right = TreeNode(2)

a = Solution.isSubtree(self, t3,t4)
print(a)

Apparently self.isSubtree(s.left, t) is what's causing this error. Can some one help me understand how to properly call recursive functions like these locally please?

Solution

You are creating the object wrong way - Change this -

a = Solution.isSubtree(self, t3,t4)

to This

a = Solution()
a.isSubtree(t3,t4)

Answered By - Pratik Patil