<p>Given two integer arrays <code>preorder</code> and <code>inorder</code> where <code>preorder</code> is the preorder traversal of a binary tree and <code>inorder</code> is the inorder traversal of the same tree, construct and return <em>the binary tree</em>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/02/19/tree.jpg" style="width: 277px; height: 302px;" />
<pre>
<strong>Input:</strong> preorder = [3,9,20,15,7], inorder = [9,3,15,20,7]
<strong>Output:</strong> [3,9,20,null,null,15,7]
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> preorder = [-1], inorder = [-1]
<strong>Output:</strong> [-1]
</pre>

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

<ul>
	<li><code>1 &lt;= preorder.length &lt;= 3000</code></li>
	<li><code>inorder.length == preorder.length</code></li>
	<li><code>-3000 &lt;= preorder[i], inorder[i] &lt;= 3000</code></li>
	<li><code>preorder</code> and <code>inorder</code> consist of <strong>unique</strong> values.</li>
	<li>Each value of <code>inorder</code> also appears in <code>preorder</code>.</li>
	<li><code>preorder</code> is <strong>guaranteed</strong> to be the preorder traversal of the tree.</li>
	<li><code>inorder</code> is <strong>guaranteed</strong> to be the inorder traversal of the tree.</li>
</ul>

/**
 * 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:
    TreeNode* buildTree(vector<int>& preorder, vector<int>& inorder) {
        
        while(preorder.size() > 0 && search(inorder, preorder[0]) == -1){
            preorder = vector(preorder.begin() + 1, preorder.end());
        }
        if(preorder.size() < 1){
            return nullptr;
        }

        TreeNode* currentNode = new TreeNode(preorder[0]);
        int nodeIndex = search(inorder, preorder[0]);
        vector<int> left = vector(inorder.begin(), inorder.begin() + nodeIndex);
        vector<int> right = vector(inorder.begin() + nodeIndex + 1, inorder.end());
        vector<int> nextNode = vector(preorder.begin() + 1, preorder.end());

        if(left.size() > 0)
            currentNode->left = buildTree(nextNode, left);
        if(right.size() > 0)
            currentNode->right = buildTree(nextNode, right);
        return currentNode;
    }
    


    int search(vector<int>& inorder, int key){
        for(int i = 0; i < inorder.size(); i++){
            if(inorder[i] == key)
                return i;
        }
        return -1;
    }
};
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