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

<p>A subtree of a binary tree <code>tree</code> is a tree that consists of a node in <code>tree</code> and all of this node&#39;s descendants. The tree <code>tree</code> could also be considered as a subtree of itself.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/04/28/subtree1-tree.jpg" style="width: 532px; height: 400px;" />
<pre>
<strong>Input:</strong> root = [3,4,5,1,2], subRoot = [4,1,2]
<strong>Output:</strong> true
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/04/28/subtree2-tree.jpg" style="width: 502px; height: 458px;" />
<pre>
<strong>Input:</strong> root = [3,4,5,1,2,null,null,null,null,0], subRoot = [4,1,2]
<strong>Output:</strong> false
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li>The number of nodes in the <code>root</code> tree is in the range <code>[1, 2000]</code>.</li>
	<li>The number of nodes in the <code>subRoot</code> tree is in the range <code>[1, 1000]</code>.</li>
	<li><code>-10<sup>4</sup> &lt;= root.val &lt;= 10<sup>4</sup></code></li>
	<li><code>-10<sup>4</sup> &lt;= subRoot.val &lt;= 10<sup>4</sup></code></li>
</ul>

class Solution {
   public:
    // CONSTANTS
    const int MOD_1 = 1000000007;
    const int MOD_2 = 2147483647;

    // Hashing a Node
    pair<unsigned long long, unsigned long long> hashSubtreeAtNode(TreeNode* node, bool needToAdd) {
        if (node == nullptr) return {3, 7};

        auto left = hashSubtreeAtNode(node->left, needToAdd);
        auto right = hashSubtreeAtNode(node->right, needToAdd);

        auto left1 = (left.first << 5) % MOD_1;
        auto right1 = (right.first << 1) % MOD_1;
        auto left2 = (left.second << 7) % MOD_2;
        auto right2 = (right.second << 1) % MOD_2;

        pair hashpair = {(left1 + right1 + node->val) % MOD_1,
                         (left2 + right2 + node->val) % MOD_2};

        if (needToAdd) memo.push_back(hashpair);

        return hashpair;
    }

    // Vector to store hashed value of each node.
    vector<pair<unsigned long long, unsigned long long>> memo;

    bool isSubtree(TreeNode* root, TreeNode* subRoot) {
        // Calling and adding hash to vector
        hashSubtreeAtNode(root, true);

        // Storing hashed value of subRoot for comparison
        pair<unsigned long long, unsigned long long> s = hashSubtreeAtNode(subRoot, false);

        // Check if hash of subRoot is present in memo
        return find(memo.begin(), memo.end(), s) != memo.end();
    }
};
31000