# Subtree Of Another Tree Problem

## Description

LeetCode Problem 572.

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:

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

Example 2:

``````1
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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].
• -10^4 <= root.val <= 10^4
• -10^4 <= subRoot.val <= 10^4

## Sample C++ Code

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/**
* Definition for a binary tree node.
* struct TreeNode {
*     int val;
*     TreeNode *left;
*     TreeNode *right;
*     TreeNode() : val(0), left(nullptr), right(nullptr) {}
*     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
*     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
* };
*/
class Solution {
public:
bool equal(TreeNode *x, TreeNode *y) {
if (x == NULL && y == NULL)
return true;
if (x == NULL || y == NULL)
return false;
return (x->val == y->val) && equal(x->left, y->left) && equal(x->right, y->right);
}

bool isSubtree(TreeNode* s, TreeNode* t) {
return (s != NULL) && ((equal(s, t)) || isSubtree(s->left, t) || isSubtree(s->right, t));
}
};
``````