<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>

class Solution {
private:
    int position(int element,vector<int> inorder){
        for(int i=0;i<inorder.size();i++){
            if(inorder[i] == element) return i;
        }
        return -1;
    }
    TreeNode* solve(int &i,int min,int max,vector<int> &preorder,vector<int> inorder){
        if(i>=preorder.size() || max<min) return NULL;
        TreeNode* node = new TreeNode(preorder[i++]);
        int index = position(node->val,inorder);

        node->left = solve(i,min,index-1,preorder,inorder);
        node->right = solve(i,index+1,max,preorder,inorder);

        return node;
    }
public:
    TreeNode* buildTree(vector<int>& preorder, vector<int>& inorder) {
        int i = 0;
        return solve(i,0,preorder.size()-1,preorder,inorder); 
    }
};
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