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Delete leaf nodes with value as x

• Difficulty Level : Medium
• Last Updated : 30 Jun, 2021

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 ``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` `nullptr;``    ``root->left = deleteLeaves(root->left, x);``    ``root->right = deleteLeaves(root->right, x);` `    ``if` `(root->data == x && root->left == NULL &&``                          ``root->right == NULL) {``       ` `        ``return` `nullptr;``    ``}``    ``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`

Javascript

 ``

Output:

`Inorder traversal after deletion : 3 1 10 10`

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