Delete leaf nodes with value as x

Given a binary tree and a target integer x, delete all the leaf nodes having value as x. Also, delete the newly formed leaves with the target value as x.

Example:

Input : x = 5  
            6
         /     
        5       4
      /          
     1     2       5 
Output : 
            6
         /     
        5       4
      /     
     1     2 
Inorder Traversal is 1 5 2 6 4

Source: Microsoft Interview

We traverse the tree in postorder fashion and recursively delete the nodes. The approach is very similar to this and this problem.

C++

// CPP code to delete all leaves with given 
// value. 
#include <bits/stdc++.h> 
using namespace std; 
  
// A binary tree node 
struct Node { 
    int data; 
    struct Node *left, *right; 
}; 
  
// A utility function to allocate a new node 
struct Node* newNode(int data) 
{ 
    struct Node* newNode = new Node; 
    newNode->data = data; 
    newNode->left = newNode->right = NULL; 
    return (newNode); 
} 
  
Node* deleteLeaves(Node* root, int x) 
{ 
    if (root == NULL) 
        return NULL; 
    root->left = deleteLeaves(root->left, x); 
    root->right = deleteLeaves(root->right, x); 
  
    if (root->data == x && root->left == NULL &&  
                          root->right == NULL) { 
        delete(root); 
        return NULL; 
    } 
    return root; 
} 
  
void inorder(Node* root) 
{ 
    if (root == NULL) 
        return; 
    inorder(root->left); 
    cout << root->data << " "; 
    inorder(root->right); 
} 
  
// Driver program 
int main(void) 
{ 
    struct Node* root = newNode(10); 
    root->left = newNode(3); 
    root->right = newNode(10); 
    root->left->left = newNode(3); 
    root->left->right = newNode(1); 
    root->right->right = newNode(3); 
    root->right->right->left = newNode(3); 
    root->right->right->right = newNode(3); 
    deleteLeaves(root, 3); 
    cout << "Inorder traversal after deletion : "; 
    inorder(root); 
    return 0; 
} 

Java

// Java code to delete all leaves with given  
// value.  
class GfG {  
  
// A binary tree node  
static class Node {  
    int data;  
    Node left, right;  
} 
  
// A utility function to allocate a new node  
static Node newNode(int data)  
{  
    Node newNode = new Node();  
    newNode.data = data;  
    newNode.left = null; 
    newNode.right = null;  
    return (newNode);  
}  
  
static Node deleteLeaves(Node root, int x)  
{  
    if (root == null)  
        return null;  
    root.left = deleteLeaves(root.left, x);  
    root.right = deleteLeaves(root.right, x);  
  
    if (root.data == x && root.left == null && root.right == null) {  
  
        return null;  
    }  
    return root;  
}  
  
static void inorder(Node root)  
{  
    if (root == null)  
        return;  
    inorder(root.left);  
    System.out.print(root.data + " ");  
    inorder(root.right);  
}  
  
// Driver program  
public static void main(String[] args)  
{  
    Node root = newNode(10);  
    root.left = newNode(3);  
    root.right = newNode(10);  
    root.left.left = newNode(3);  
    root.left.right = newNode(1);  
    root.right.right = newNode(3);  
    root.right.right.left = newNode(3);  
    root.right.right.right = newNode(3);  
    deleteLeaves(root, 3);  
    System.out.print("Inorder traversal after deletion : ");  
    inorder(root);  
} 
}  

Python3

# Python3 code to delete all leaves
# with given value.

# A utility class to allocate a new node
class newNode:
def __init__(self, data):
self.data = data
self.left = self.right = None

def deleteLeaves(root, x):
if (root == None):
return None
root.left = deleteLeaves(root.left, x)
root.right = deleteLeaves(root.right, x)

if (root.data == x and
root.left == None and
root.right == None):
return None
return root

def inorder(root):
if (root == None):
return
inorder(root.left)
print(root.data, end = ” “)
inorder(root.right)

# Driver Code
if __name__ == ‘__main__’:
root = newNode(10)
root.left = newNode(3)
root.right = newNode(10)
root.left.left = newNode(3)
root.left.right = newNode(1)
root.right.right = newNode(3)
root.right.right.left = newNode(3)
root.right.right.right = newNode(3)
deleteLeaves(root, 3)
print(“Inorder traversal after deletion : “)
inorder(root)

# This code is contributed by PranchalK

C#

// C# code to delete all leaves with given  
// value. 
using System; 
      
class GfG  
{  
  
    // A binary tree node  
    class Node  
    {  
        public int data;  
        public Node left, right;  
    } 
  
    // A utility function to allocate a new node  
    static Node newNode(int data)  
    {  
        Node newNode = new Node();  
        newNode.data = data;  
        newNode.left = null; 
        newNode.right = null;  
        return (newNode);  
    }  
  
    static Node deleteLeaves(Node root, int x)  
    {  
        if (root == null)  
            return null;  
        root.left = deleteLeaves(root.left, x);  
        root.right = deleteLeaves(root.right, x);  
  
        if (root.data == x &&  
            root.left == null &&  
            root.right == null)  
        {  
  
            return null;  
        }  
        return root;  
    }  
  
    static void inorder(Node root)  
    {  
        if (root == null)  
            return;  
        inorder(root.left);  
        Console.Write(root.data + " ");  
        inorder(root.right);  
    }  
  
    // Driver code  
    public static void Main(String[] args)  
    {  
        Node root = newNode(10);  
        root.left = newNode(3);  
        root.right = newNode(10);  
        root.left.left = newNode(3);  
        root.left.right = newNode(1);  
        root.right.right = newNode(3);  
        root.right.right.left = newNode(3);  
        root.right.right.right = newNode(3);  
        deleteLeaves(root, 3);  
        Console.Write("Inorder traversal after deletion : ");  
        inorder(root);  
    } 
} 
  
// This code is contributed by PrinciRaj1992 

Output:

Inorder traversal after deletion : 3 1 10 10

Delete leaf nodes with value as x

C++

Java

Python3

C#

tags:

leave a comment

0 Comments

Subscribe to Our Newsletter

Top Followed books