<p>Given two integer arrays, <code>preorder</code> and <code>postorder</code> where <code>preorder</code> is the preorder traversal of a binary tree of <strong>distinct</strong> values and <code>postorder</code> is the postorder traversal of the same tree, reconstruct and return <em>the binary tree</em>.</p>

<p>If there exist multiple answers, you can <strong>return any</strong> of them.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/07/24/lc-prepost.jpg" style="width: 304px; height: 265px;" />
<pre>
<strong>Input:</strong> preorder = [1,2,4,5,3,6,7], postorder = [4,5,2,6,7,3,1]
<strong>Output:</strong> [1,2,3,4,5,6,7]
</pre>

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

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

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

<ul>
	<li><code>1 &lt;= preorder.length &lt;= 30</code></li>
	<li><code>1 &lt;= preorder[i] &lt;= preorder.length</code></li>
	<li>All the values of <code>preorder</code> are <strong>unique</strong>.</li>
	<li><code>postorder.length == preorder.length</code></li>
	<li><code>1 &lt;= postorder[i] &lt;= postorder.length</code></li>
	<li>All the values of <code>postorder</code> are <strong>unique</strong>.</li>
	<li>It is guaranteed that <code>preorder</code> and <code>postorder</code> are the preorder traversal and postorder traversal of the same binary 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 {
    TreeNode * f(int &preIdx,vector<int>&pre,int &postIdx,vector<int>&post){
        TreeNode * root = new TreeNode(pre[preIdx++]);
        if(root->val != post[postIdx]){
            root->left = f(preIdx,pre,postIdx,post);
        }
        if(root->val != post[postIdx]){
            root->right = f(preIdx,pre,postIdx,post);
        }
        postIdx++;
        return root;
    }
public:
    TreeNode* constructFromPrePost(vector<int>& preorder, vector<int>& postorder) {
        int i = 0,j = 0;
        TreeNode * root = f(i,preorder,j,postorder);

        queue<TreeNode*>q;
        q.push(root);

        while(!q.empty()){
            int sz = q.size();
            while(sz--){
                TreeNode * node = q.front();
                q.pop();

                if(node == nullptr){
                    cout<<"# ";
                    continue;
                }
                cout<<node->val<<" ";
                q.push(node->left);
                
                q.push(node->right);
            }
            cout<<'\n';
        }
        return root;
    }
};
28800