# 1273. Delete Tree Nodes

https://leetcode.com/problems/delete-tree-nodes

## Description

A tree rooted at node 0 is given as follows:

* The number of nodes is `nodes`;
* The value of the `i`-th node is `value[i]`;
* The parent of the `i`-th node is `parent[i]`.

Remove every subtree whose sum of values of nodes is zero.

After doing so, return the number of nodes remaining in the tree.

**Example 1:**

![](https://assets.leetcode.com/uploads/2019/07/02/1421_sample_1.PNG)

```
**Input:** nodes = 7, parent = [-1,0,0,1,2,2,2], value = [1,-2,4,0,-2,-1,-1]
**Output:** 2
```

**Example 2:**

```
**Input:** nodes = 7, parent = [-1,0,0,1,2,2,2], value = [1,-2,4,0,-2,-1,-2]
**Output:** 6
```

**Example 3:**

```
**Input:** nodes = 5, parent = [-1,0,1,0,0], value = [-672,441,18,728,378]
**Output:** 5
```

**Example 4:**

```
**Input:** nodes = 5, parent = [-1,0,0,1,1], value = [-686,-842,616,-739,-746]
**Output:** 5
```

**Constraints:**

* `1 <= nodes <= 10^4`
* `parent.length == nodes`
* `0 <= parent[i] <= nodes - 1`
* `parent[0] == -1` which indicates that `0` is the root.
* `value.length == nodes`
* `-10^5 <= value[i] <= 10^5`
* The given input is **guaranteed** to represent a **valid tree**.

## ac

```java
```
