513. Find Bottom Left Tree Value**

513. Find Bottom Left Tree Value**

https://leetcode.com/problems/find-bottom-left-tree-value/

Title Description

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

Note: You may assume the tree (i.e., the given root node) is not NULL.

C ++ implementation 1

Sequence through each layer, each time the number of updates leftmost.

class Solution {
public:
    int findBottomLeftValue(TreeNode* root) {

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

        int res = 0;
        while (!Queue.empty()) {

            int size = Queue.size();
            res = Queue.front()->val;
            for (int i = size; i > 0; --i) {
                auto root = Queue.front();
                Queue.pop();
                if (root->left)
                    Queue.push(root->left);
                if (root->right)
                    Queue.push(root->right);
            }
        }
        return res;
    }
};