513. Find Bottom Left Tree Value（LeetCode）

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

Example 1:

Input:

    2
   / 
  1   3

Output:
1

Example 2: 

Input:

        1
       / 
      2   3
     /   / 
    4   5   6
       /
      7

Output:
7

/**
 * 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 rlt;
        queue<TreeNode*> nodes;
        nodes.push(root);
        while (!nodes.empty())
        {
            int _size = nodes.size();
            cout<<_size<<endl;
            rlt = nodes.front()->val;
           // cout<<rlt<<endl;
            while (_size)
            {
                TreeNode* tmp = nodes.front();
                nodes.pop();
                if (tmp->left)
                {
                    nodes.push(tmp->left);
                }
                if (tmp->right)
                {
                    nodes.push(tmp->right);
                }
                _size--;
            }

        }
        return rlt;
    }
};