python straightforward level-order traversal using BFS
py\n# Definition for a binary tree node.\n# class TreeNode:\n#     def __init__(self, val=0, left=None, right=None):\n#         self.val = val\n#         self.l
```py\n# Definition for a binary tree node.\n# class TreeNode:\n#     def __init__(self, val=0, left=None, right=None):\n#         self.val = val\n#         self.left = left\n#         self.right = right\n\nimport collections\n\nclass Solution:\n    def findBottomLeftValue(self, root: TreeNode) -> int:\n        left = None\n        queue = collections.deque([root])\n        while queue:\n            size = len(queue)\n            left = queue[0].val\n            for _ in range(size):\n                node = queue.popleft()\n                if node.left:\n                    queue.append(node.left)\n                if node.right:\n                    queue.append(node.right)\n            \n            \n        return left\n```
['Breadth-First Search', 'Python']