Find Bottom Left Tree Value

Given a binary tree, find the leftmost value in the last row of the tree.

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    int findBottomLeftValue(TreeNode* root) {
        int maxlevel = 0,curlevel;
        TreeNode* ROOT;
        queue<int> level;
		queue<TreeNode*> q;
		q.push(root); 
		level.push(0);
		ROOT = root;
		while(q.size())
		{
			TreeNode* r = q.front();
			curlevel = level.front();
			level.pop();
			q.pop();
			if(r->left)
			{
				q.push(r->left);
				level.push(curlevel + 1);
		    }
			if(r->right)
			{
				q.push(r->right);
				level.push(curlevel + 1);
		    }
			if(curlevel > maxlevel)
			{
				maxlevel = curlevel;
				ROOT = r;
			}
		}
		return ROOT->val;
    }
};