# Find Bottom Left Tree Value Problem

## Description

LeetCode Problem 513.

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

Example 1:

``````1
2
Input: root = [2,1,3]
Output: 1
``````

Example 2:

``````1
2
Input: root = [1,2,3,4,null,5,6,null,null,7]
Output: 7
``````

Constraints:

• The number of nodes in the tree is in the range [1, 10^4].
• -2^31 <= Node.val <= 2^31 - 1

## Sample C++ Code

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/**
* 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:
int findBottomLeftValue(TreeNode* root) {
if (root == NULL)
return 0;

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

TreeNode* curr;
int len, leftmost;

while (!bfsQ.empty()) {
len = bfsQ.size();

for (int i = 0; i < len; i ++) {
curr = bfsQ.front();
bfsQ.pop();

if (i == 0)
leftmost = curr->val;

if (curr->left != NULL)
bfsQ.push(curr->left);

if (curr->right != NULL)
bfsQ.push(curr->right);
}
}

return leftmost;
}
};
``````