<p>Given the <code>root</code> of a binary tree, return the leftmost value in the last row of the tree.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2020/12/14/tree1.jpg" style="width: 302px; height: 182px;" />
<pre>
<strong>Input:</strong> root = [2,1,3]
<strong>Output:</strong> 1
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2020/12/14/tree2.jpg" style="width: 432px; height: 421px;" />
<pre>
<strong>Input:</strong> root = [1,2,3,4,null,5,6,null,null,7]
<strong>Output:</strong> 7
</pre>

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

<ul>
	<li>The number of nodes in the tree is in the range <code>[1, 10<sup>4</sup>]</code>.</li>
	<li><code>-2<sup>31</sup> &lt;= Node.val &lt;= 2<sup>31</sup> - 1</code></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:

    vector <pair<int,int>> v;

    void solver(TreeNode * root)
    {
        queue <pair<TreeNode *,int>> q;
        q.push({root,0});

        while(!q.empty())
        {
            auto p = q.front();
            TreeNode * par = p.first;
            int level = p.second;
            q.pop();

            v.push_back({par->val,level});

            if(par->left)
            {
                q.push({par->left,level+1});
            }

            if(par->right)
            {
                q.push({par->right,level+1});
            }
        }
    }

    int maxH(TreeNode * root)
    {
        if(root == NULL) return 0;

        int l = maxH(root->left);
        int r = maxH(root->right);

        return max(l,r) + 1;
    }

    int findBottomLeftValue(TreeNode* root) 
    {
        solver(root);

        int sz = maxH(root)-1;
        cout << sz;

        for(int i=0;i<v.size();i++)
        {
            if(v[i].second == sz) return v[i].first;
        }

        return 0;
    }
};
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