> For the complete documentation index, see [llms.txt](https://timmybeeflin.gitbook.io/cracking-leetcode/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://timmybeeflin.gitbook.io/cracking-leetcode/tree/2458.-height-of-binary-tree-after-subtree-removal-queries.md).

# 2458. Height of Binary Tree After Subtree Removal Queries

### initial thought, too slow

```
T: O(n * q), queries times
S: O(q)
```

```java
/**
 * 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 int[] treeQueries(TreeNode root, int[] queries) {
        int[] result = new int[queries.length];
        for (int i = 0; i < queries.length; i++) {
            result[i] = calHeight(root, queries[i]) - 1;
        }
        return result;
    }
    private int calHeight(TreeNode node, int remove) {
        if (node == null) {
            return 0;
        }
        int left = 0;
        int right = 0;
        if (node.val != remove) {
            left = calHeight(node.left, remove);
            right = calHeight(node.right, remove);
        } else {
            return 0;
        }
        return Math.max(left, right) + 1;
    }
}

/**
remove 
cal height again

 */
```

so we need cache!! and other way to do it

```
T: O(n + q), querie times
S: O(n)
```

```java
class Solution {

    public int[] treeQueries(TreeNode root, int[] queries) {
        Map<Integer, Integer> heightMap = new HashMap<>();
        Map<Integer, Integer> resultMap = new HashMap<>();
        dfs(root, heightMap, resultMap, 0, 0);

        int[] result = new int[queries.length];
        for (int i = 0; i < queries.length; i++) {
            result[i] = resultMap.get(queries[i]);
        }
        return result;
    }
    private int getNodeHeight(TreeNode node, Map<Integer, Integer> heightMap) {
        if (node == null) {
            return -1;
        }
        if (heightMap.containsKey(node.val)) {
            return heightMap.get(node.val);
        }
        int height = 1 + Math.max(getNodeHeight(node.left, heightMap), getNodeHeight(node.right, heightMap));
        heightMap.put(node.val, height);
        return height;
    }
    private void dfs(TreeNode node, Map<Integer, Integer> heightMap, Map<Integer, Integer> resultMap, int depth, int max) {
        if (node == null) {
            return;
        }
        resultMap.put(node.val, max);
        int nextDepth = depth+1;
        int leftHeight = getNodeHeight(node.left, heightMap);
        int rightHeight = getNodeHeight(node.right, heightMap);

        dfs(node.left, heightMap, resultMap, nextDepth, Math.max(max, nextDepth + rightHeight));
        dfs(node.right, heightMap, resultMap, nextDepth, Math.max(max, nextDepth + leftHeight));
    }
}

/**
idea is we get each node's height first

then cal each remove node's max height
how to cal this?

  1
 2. 3
4 5.  6

for example 

if we remove node 2, then the ans should the cur depth + the hight of same level right subtree (3 and 6)

  1 -> node
 2.  dfs(node.left 2...) 
4 5.  

3
  6
height(node.right... 3) = 1
-> max = Math.max(max, depth(1) + the hight of same level right subtree (3 and 6) (height is 1)
= Math.max(0, 1 + 1) = 2

why need max???

ex:

        1
       / \
      2   3
     /     \
    4       5
           / \
          6   7

for removing 4

cal the cur_depth + rightSubtree (-1) = 2 + -1 = 1 -> 

 2
/
4

cur_depth + height(2's right, it's null so -1)
= 2 + -1 = 1
rightSubtree is null, so no more height can add to depth(1, which is in node 2 aspect) 反而變小了！

but actually ans is 3 (from right side max = 3)
so we need maxVal for the later ans!


T: O(n + q), querie times
S: O(n)
 */
```

<figure><img src="/files/A9x1yPwiRJ68hM6BLo1O" alt=""><figcaption></figcaption></figure>

<figure><img src="/files/jx0mvfZ3yg4R57QYS4Dc" alt=""><figcaption></figcaption></figure>

<figure><img src="/files/UUjPsvLsKkaV1AMgHr9p" alt=""><figcaption></figcaption></figure>


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://timmybeeflin.gitbook.io/cracking-leetcode/tree/2458.-height-of-binary-tree-after-subtree-removal-queries.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.