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1325. Delete Leaves With a Given Value

Description

Given a binary tree root and an integer target, delete all the leaf nodes with value target.

Note that once you delete a leaf node with value target, if its parent node becomes a leaf node and has the value target, it should also be deleted (you need to continue doing that until you cannot).

 

Example 1:

Input: root = [1,2,3,2,null,2,4], target = 2
Output: [1,null,3,null,4]
Explanation: Leaf nodes in green with value (target = 2) are removed (Picture in left). 
After removing, new nodes become leaf nodes with value (target = 2) (Picture in center).

Example 2:

Input: root = [1,3,3,3,2], target = 3
Output: [1,3,null,null,2]

Example 3:

Input: root = [1,2,null,2,null,2], target = 2
Output: [1]
Explanation: Leaf nodes in green with value (target = 2) are removed at each step.

 

Constraints:

• The number of nodes in the tree is in the range [1, 3000].
• 1 <= Node.val, target <= 1000

Solutions

• Java
• C++
• Python
• Go
• TypeScript

• /**
   * Definition for a binary tree node.
   * public class TreeNode {
   *     int val;
   *     TreeNode left;
   *     TreeNode right;
   *     TreeNode() {}
   *     TreeNode(int val) { this.val = val; }
   *     TreeNode(int val, TreeNode left, TreeNode right) {
   *         this.val = val;
   *         this.left = left;
   *         this.right = right;
   *     }
   * }
   */
  class Solution {
      public TreeNode removeLeafNodes(TreeNode root, int target) {
          if (root == null) {
              return null;
          }
          root.left = removeLeafNodes(root.left, target);
          root.right = removeLeafNodes(root.right, target);
          if (root.left == null && root.right == null && root.val == target) {
              return null;
          }
          return root;
      }
  }
  

• /**
   * Definition for a binary tree node.
   * struct TreeNode {
   *     int val;
   *     TreeNode *left;
   *     TreeNode *right;
   *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
   *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
   *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
   * };
   */
  class Solution {
  public:
      TreeNode* removeLeafNodes(TreeNode* root, int target) {
          if (!root) {
              return nullptr;
          }
          root->left = removeLeafNodes(root->left, target);
          root->right = removeLeafNodes(root->right, target);
          if (!root->left && !root->right && root->val == target) {
              return nullptr;
          }
          return root;
      }
  };
  

• # Definition for a binary tree node.
  # class TreeNode:
  #     def __init__(self, val=0, left=None, right=None):
  #         self.val = val
  #         self.left = left
  #         self.right = right
  class Solution:
      def removeLeafNodes(
          self, root: Optional[TreeNode], target: int
      ) -> Optional[TreeNode]:
          if root is None:
              return None
          root.left = self.removeLeafNodes(root.left, target)
          root.right = self.removeLeafNodes(root.right, target)
          if root.left is None and root.right is None and root.val == target:
              return None
          return root
  
  

• /**
   * Definition for a binary tree node.
   * type TreeNode struct {
   *     Val int
   *     Left *TreeNode
   *     Right *TreeNode
   * }
   */
  func removeLeafNodes(root *TreeNode, target int) *TreeNode {
  	if root == nil {
  		return nil
  	}
  	root.Left = removeLeafNodes(root.Left, target)
  	root.Right = removeLeafNodes(root.Right, target)
  	if root.Left == nil && root.Right == nil && root.Val == target {
  		return nil
  	}
  	return root
  }
  

• /**
   * Definition for a binary tree node.
   * class TreeNode {
   *     val: number
   *     left: TreeNode | null
   *     right: TreeNode | null
   *     constructor(val?: number, left?: TreeNode | null, right?: TreeNode | null) {
   *         this.val = (val===undefined ? 0 : val)
   *         this.left = (left===undefined ? null : left)
   *         this.right = (right===undefined ? null : right)
   *     }
   * }
   */
  
  function removeLeafNodes(root: TreeNode | null, target: number): TreeNode | null {
      if (!root) {
          return null;
      }
      root.left = removeLeafNodes(root.left, target);
      root.right = removeLeafNodes(root.right, target);
      if (!root.left && !root.right && root.val == target) {
          return null;
      }
      return root;
  }
  
  

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