572. Subtree of Another Tree ⭐
Medium
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:

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

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
/**
* Definition for a binary tree node.
* type TreeNode struct {
* Val int
* Left *TreeNode
* Right *TreeNode
* }
*/
func isSubtree(root *TreeNode, subRoot *TreeNode) bool {
if root == nil {
return false
}
if isSame(root, subRoot) { return true }
return isSubtree(root.Left, subRoot) || isSubtree(root.Right, subRoot)
}
func isSame(root *TreeNode, subRoot *TreeNode) bool {
if root == nil && subRoot == nil { return true }
if root == nil || subRoot == nil { return false }
if root.Val != subRoot.Val { return false }
return isSame(root.Left, subRoot.Left) && isSame(root.Right, subRoot.Right)
}