CODEWITHSUNDEEP
python-3.xalgorithmdata-structurestree
Harsh
Harsh

Reputation: 169

I am trying to build BST in python from scratch RecursionError: maximum recursion depth exceeded in comparison

I am trying to build tree from scratch but getting Maximum recursion error. Kindly, Help me to find the error.

First i created a node and with make_node function, i am trying to build tree. then with the help of inorder function i am trying to print the data in the node.

class node:
    def __init__(self,data):
        self.data = data
        self.left = None;
        self.right = None;

class tree:
    def __init__(self):
        self.start = None;
    def make_node(self,data):
        if(self.start==None):
            self.start = node(data)
            print(self.start.data)
            return
        
        #temp = self.start
        if(self.start.data<data):
            if(self.start.left == None):
                print(self.start.left.data)
                self.start.left = node(data)
            else:
                self.start.left(self.make_node(data))
        elif(self.start.data>=data):
            print(self.start.right.data)
            if(self.start.right == None):
                self.start.right = node(data)
            else:
                self.start.right(self.make_node(data))
    
    def inorder(self):
        #temp2 = self.start
        if(self.start==None):
            return
        self.start = self.start
        self.inorder(self.start.left)
        print(self.start.data)
        self.inoder(self.start.right)
        

BST = tree()
BST.make_node(2)
BST.make_node(3)
BST.make_node(4)
BST.make_node(5)

BST.inorder()

Can you guys help me to find my mistakes. Thanks in advance.

Upvotes: 1

Views: 56

Answers (2)

Yash Shah
Yash Shah

Reputation: 1654

Errors I have found:

1. You can't call the function like this: self.start.left(self.make_node(data)). As self refers to the object of the tree, not an object of the node. For referencing Node object you can pass as a parameter. So, I have rectified this error everywhere in your code.

2. Also, you have used inequalities in opposite order i.e. larger element on the left side of the root and smaller element in the right... which I have changed in the code below.

Node Class:

class node:
    def __init__(self,data):
        self.data = data
        self.left = None;
        self.right = None;

Tree Class:

class tree:
    
    def __init__(self):
        self.start = None;
    
    def make_node(self,Node,data):
        
        if(Node == None):
            Node = node(data)
            if(self.start == None):
                self.start = Node
            return Node
        
        if(Node.data>data):
            Node.left = self.make_node(Node.left,data)
        elif(Node.data<=data):
            Node.right = self.make_node(Node.right,data)
            
        return Node
    
    def inorder(self,root):
        if(root==None):
            return
        self.inorder(root.left)
        print(root.data)
        self.inorder(root.right)

Building a tree and using inorder Function:

BST = tree()
BST.make_node(BST.start,2)
BST.make_node(BST.start,3)
BST.make_node(BST.start,4)
BST.make_node(BST.start,5)

BST.inorder(BST.start)

Upvotes: 1

spag
spag

Reputation: 1

You can check the recursion limit with sys.getrecursionlimit:

import sys print(sys.getrecursionlimit())

then change the limit with sys.getrecursionlimit():

sys.setrecursionlimit(10**6)

Upvotes: 0

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