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## Problem

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

Example 1:

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


Example 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

## Code

class Solution {
public int findBottomLeftValue(TreeNode root) {
if(root == null) return -1;

queue.offer(root);

while(!queue.isEmpty()) {
root = queue.poll();

if(root.right != null) queue.offer(root.right);
if(root.left != null) queue.offer(root.left);
}

return root.val;
}
}

class Solution {
public int findBottomLeftValue(TreeNode root) {
if(root == null) return -1;

queue.offer(root);

int left = root.val;

while(!queue.isEmpty()) {
int size = queue.size();

for(int i = 0; i < size; i++) {
TreeNode node = queue.poll();

if(i == 0) {
left = node.val;
}

if(node.left != null) queue.offer(node.left);
if(node.right != null) queue.offer(node.right);
}
}

return left;
}
}