# GeetCode Hub

Given the `root` of a binary tree, return the same tree where every subtree (of the given tree) not containing a `1` has been removed.

A subtree of a node `node` is `node` plus every node that is a descendant of `node`.

Example 1:

```Input: root = [1,null,0,0,1]
Output: [1,null,0,null,1]
Explanation:
Only the red nodes satisfy the property "every subtree not containing a 1".
The diagram on the right represents the answer.
```

Example 2:

```Input: root = [1,0,1,0,0,0,1]
Output: [1,null,1,null,1]
```

Example 3:

```Input: root = [1,1,0,1,1,0,1,0]
Output: [1,1,0,1,1,null,1]
```

Constraints:

• The number of nodes in the tree is in the range `[1, 200]`.
• `Node.val` is either `0` or `1`.

/** * 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 pruneTree(TreeNode root) { } }