# 572. Subtree of Another Tree

Given the roots of two binary trees `root` and `subRoot`, return `true` if there is a subtree of `root` with the same structure and node values of `subRoot` and `false` otherwise.

A subtree of a binary tree `tree` is a tree that consists of a node in `tree` and all of this node's descendants. The tree `tree` could also be considered as a subtree of itself.

**Example 1:**![](https://assets.leetcode.com/uploads/2021/04/28/subtree1-tree.jpg)

```
Input: root = [3,4,5,1,2], subRoot = [4,1,2]
Output: true
```

**Example 2:**![](https://assets.leetcode.com/uploads/2021/04/28/subtree2-tree.jpg)

```
Input: root = [3,4,5,1,2,null,null,null,null,0], subRoot = [4,1,2]
Output: false
```

**Constraints:**

* The number of nodes in the `root` tree is in the range `[1, 2000]`.
* The number of nodes in the `subRoot` tree is in the range `[1, 1000]`.
* `-104 <= root.val <= 104`
* `-104 <= subRoot.val <= 104`

## Solution

Adapt the method of 100. same tree to recursively check the status

```java
class Solution {
    public boolean isSubtree(TreeNode root, TreeNode subRoot) {
        if(root == null && subRoot != null) return false;
        if(isSameTree(root, subRoot)) return true;
        return isSubtree(root.left, subRoot) || isSubtree(root.right, subRoot);
    }
    
    public boolean isSameTree(TreeNode node1, TreeNode node2){
        
        if(node1 == null && node2 == null) return true;
        if(node1 == null || node2 == null) return false;
        if(node1.val != node2.val) return false;
        return isSameTree(node1.left, node2.left) && isSameTree(node1.right, node2.right);   
        
    }
    
}
```
