# Print all odd nodes of Binary Search Tree

Given a binary search tree. The task is to print all odd nodes of the binary search tree.

Examples:

```Input :
5
/   \
3     7
/ \   / \
2   4 6   8
Output : 3 5 7

Input :
14
/   \
12    17
/ \   / \
8  13 16   19
Output : 13 17 19
```

Approach: Traverse the Binary Search tree using any of the tree traversals and check if current node’s value is odd. If yes then print it otherwise skip that node.

Below is the implementation of the above Approach:

## C++

 `// C++ program to print all odd node of BST ` `#include ` `using` `namespace` `std; ` ` `  `// create Tree ` `struct` `Node { ` `    ``int` `key; ` `    ``struct` `Node *left, *right; ` `}; ` ` `  `// A utility function to create a new BST node ` `Node* newNode(``int` `item) ` `{ ` `    ``Node* temp = ``new` `Node; ` `    ``temp->key = item; ` `    ``temp->left = temp->right = NULL; ` `    ``return` `temp; ` `} ` ` `  `// A utility function to do inorder traversal of BST ` `void` `inorder(Node* root) ` `{ ` `    ``if` `(root != NULL) { ` `        ``inorder(root->left); ` `        ``printf``(``"%d "``, root->key); ` `        ``inorder(root->right); ` `    ``} ` `} ` ` `  `/* A utility function to insert a new node  ` `   ``with given key in BST */` `Node* insert(Node* node, ``int` `key) ` `{ ` `    ``/* If the tree is empty, return a new node */` `    ``if` `(node == NULL) ` `        ``return` `newNode(key); ` ` `  `    ``/* Otherwise, recur down the tree */` `    ``if` `(key < node->key) ` `        ``node->left = insert(node->left, key); ` `    ``else` `        ``node->right = insert(node->right, key); ` ` `  `    ``/* return the (unchanged) node pointer */` `    ``return` `node; ` `} ` ` `  `// Function to print all odd nodes ` `void` `oddNode(Node* root) ` `{ ` `    ``if` `(root != NULL) { ` `        ``oddNode(root->left); ` ` `  `        ``// if node is odd then print it ` `        ``if` `(root->key % 2 != 0) ` `            ``printf``(``"%d "``, root->key); ` ` `  `        ``oddNode(root->right); ` `    ``} ` `} ` ` `  `// Driver Code ` `int` `main() ` `{ ` `    ``/* Let us create following BST   ` `        ``5   ` `      ``/  \   ` `     ``3    7   ` `    ``/ \  / \   ` `    ``2 4  6 8 */` `    ``Node* root = NULL; ` `    ``root = insert(root, 5); ` `    ``root = insert(root, 3); ` `    ``root = insert(root, 2); ` `    ``root = insert(root, 4); ` `    ``root = insert(root, 7); ` `    ``root = insert(root, 6); ` `    ``root = insert(root, 8); ` ` `  `    ``oddNode(root); ` ` `  `    ``return` `0; ` `} `

## Java

 `// Java program to print all odd node of BST  ` `class` `GfG {  ` ` `  `// create Tree  ` `static` `class` `Node {  ` `    ``int` `key;  ` `    ``Node left, right;  ` `}  ` ` `  `// A utility function to create a new BST node  ` `static` `Node newNode(``int` `item)  ` `{  ` `    ``Node temp = ``new` `Node();  ` `    ``temp.key = item;  ` `    ``temp.left = ``null``; ` `    ``temp.right = ``null``;  ` `    ``return` `temp;  ` `}  ` ` `  `// A utility function to do inorder traversal of BST  ` `static` `void` `inorder(Node root)  ` `{  ` `    ``if` `(root != ``null``) {  ` `        ``inorder(root.left);  ` `        ``System.out.print(root.key + ``" "``);  ` `        ``inorder(root.right);  ` `    ``}  ` `}  ` ` `  `/* A utility function to insert a new node  ` `with given key in BST */` `static` `Node insert(Node node, ``int` `key)  ` `{  ` `    ``/* If the tree is empty, return a new node */` `    ``if` `(node == ``null``)  ` `        ``return` `newNode(key);  ` ` `  `    ``/* Otherwise, recur down the tree */` `    ``if` `(key < node.key)  ` `        ``node.left = insert(node.left, key);  ` `    ``else` `        ``node.right = insert(node.right, key);  ` ` `  `    ``/* return the (unchanged) node pointer */` `    ``return` `node;  ` `}  ` ` `  `// Function to print all odd nodes  ` `static` `void` `oddNode(Node root)  ` `{  ` `    ``if` `(root != ``null``) {  ` `        ``oddNode(root.left);  ` ` `  `        ``// if node is odd then print it  ` `        ``if` `(root.key % ``2` `!= ``0``)  ` `            ``System.out.print(root.key + ``" "``);  ` ` `  `        ``oddNode(root.right);  ` `    ``}  ` `}  ` ` `  `// Driver Code  ` `public` `static` `void` `main(String[] args)  ` `{  ` `    ``/* Let us create following BST  ` `        ``5  ` `    ``/ \  ` `    ``3 7  ` `    ``/ \ / \  ` `    ``2 4 6 8 */` `    ``Node root = ``null``;  ` `    ``root = insert(root, ``5``);  ` `    ``root = insert(root, ``3``);  ` `    ``root = insert(root, ``2``);  ` `    ``root = insert(root, ``4``);  ` `    ``root = insert(root, ``7``);  ` `    ``root = insert(root, ``6``);  ` `    ``root = insert(root, ``8``);  ` ` `  `    ``oddNode(root);  ` ` `  `}  ` `}  `

## Python3

# Python3 program to print all odd
# node of BST

# create Tree
# to create a new BST node
class newNode:

# Construct to create a new node
def __init__(self, key):
self.key = key
self.left = None
self.right = None

# A utility function to do inorder
# traversal of BST
def inorder( root) :

if (root != None):
inorder(root.left)
print(root.key, end = ” “)
inorder(root.right)

“”” A utility function to insert a
new node with given key in BST “””
def insert(node, key):

“”” If the tree is empty,
return a new node “””
if (node == None):
return newNode(key)

“”” Otherwise, recur down the tree “””
if (key < node.key): node.left = insert(node.left, key) else: node.right = insert(node.right, key) """ return the (unchanged) node pointer """ return node # Function to prall even nodes def oddNode(root) : if (root != None): oddNode(root.left) # if node is even then prit if (root.key % 2 != 0): print(root.key, end = " ") oddNode(root.right) # Driver Code if __name__ == '__main__': """ Let us create following BST 5 / \ 3 7 / \ / \ 2 4 6 8 """ root = None root = insert(root, 5) root = insert(root, 3) root = insert(root, 2) root = insert(root, 4) root = insert(root, 7) root = insert(root, 6) root = insert(root, 8) oddNode(root) # This code is contributed by # Shubham Singh(SHUBHAMSINGH10) [tabby title="C#"]

 `// C# program to print all odd node of BST ` `using` `System; ` ` `  `public` `class` `GfG  ` `{  ` ` `  `// create Tree  ` `class` `Node  ` `{  ` `    ``public` `int` `key;  ` `    ``public` `Node left, right;  ` `}  ` ` `  `// A utility function to create a new BST node  ` `static` `Node newNode(``int` `item)  ` `{  ` `    ``Node temp = ``new` `Node();  ` `    ``temp.key = item;  ` `    ``temp.left = ``null``;  ` `    ``temp.right = ``null``;  ` `    ``return` `temp;  ` `}  ` ` `  `// A utility function to do  ` `// inorder traversal of BST  ` `static` `void` `inorder(Node root)  ` `{  ` `    ``if` `(root != ``null``) ` `    ``{  ` `        ``inorder(root.left);  ` `        ``Console.Write(root.key + ``" "``);  ` `        ``inorder(root.right);  ` `    ``}  ` `}  ` ` `  `/* A utility function to insert a new node  ` `with given key in BST */` `static` `Node insert(Node node, ``int` `key)  ` `{  ` `    ``/* If the tree is empty, return a new node */` `    ``if` `(node == ``null``)  ` `        ``return` `newNode(key);  ` ` `  `    ``/* Otherwise, recur down the tree */` `    ``if` `(key < node.key)  ` `        ``node.left = insert(node.left, key);  ` `    ``else` `        ``node.right = insert(node.right, key);  ` ` `  `    ``/* return the (unchanged) node pointer */` `    ``return` `node;  ` `}  ` ` `  `// Function to print all odd nodes  ` `static` `void` `oddNode(Node root)  ` `{  ` `    ``if` `(root != ``null``)  ` `    ``{  ` `        ``oddNode(root.left);  ` ` `  `        ``// if node is odd then print it  ` `        ``if` `(root.key % 2 != 0)  ` `            ``Console.Write(root.key + ``" "``);  ` ` `  `        ``oddNode(root.right);  ` `    ``}  ` `}  ` ` `  `// Driver Code  ` `public` `static` `void` `Main(String[] args)  ` `{  ` `    ``/* Let us create following BST  ` `        ``5  ` `    ``/ \  ` `    ``3 7  ` `    ``/ \ / \  ` `    ``2 4 6 8 */` `    ``Node root = ``null``;  ` `    ``root = insert(root, 5);  ` `    ``root = insert(root, 3);  ` `    ``root = insert(root, 2);  ` `    ``root = insert(root, 4);  ` `    ``root = insert(root, 7);  ` `    ``root = insert(root, 6);  ` `    ``root = insert(root, 8);  ` ` `  `    ``oddNode(root);  ` ` `  `}  ` `}  ` ` `  `// This code has been contributed  ` `// by PrinciRaj1992 `

Output:

```3 5 7
```

Time Complexity : O(n) where n is no. Of nodes

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