Sure, here is a Python solution for the problem:

```python
class Solution(object):
def sumOfLeftLeaves(self, root):
"""
:type root: TreeNode
:rtype: int
"""
if not root:
return 0
elif self.isLeaf(root.left):
return root.left.val + self.sumOfLeftLeaves(root.right)
else:
return self.sumOfLeftLeaves(root.left) + self.sumOfLeftLeaves(root.right)

def isLeaf(self, node):
if not node:
return False
if not node.left and not node.right:
return True
return False
```

Here is a step by step explanation of the code:

1. We define a class `Solution` with two methods: `sumOfLeftLeaves` and `isLeaf`.
2. `sumOfLeftLeaves` is the main function that takes the root of the binary tree as input and returns the sum of all left leaves.
3. If the root is `None`, we return 0 because there are no leaves in an empty tree.
4. If the left child of the root is a leaf node, we add its value to the sum of left leaves of the right subtree.
5. If the left child of the root is not a leaf node, we recursively find the sum of left leaves in the left and right subtrees.
6. `isLeaf` is a helper function that checks if a node is a leaf node. A node is a leaf node if it does not have any children. If the node is `None` or it has any child, it is not a leaf node.

Question

Sure, here is a Python solution for the problem:

```python
class Solution(object):
    def sumOfLeftLeaves(self, root):
        """
        :type root: TreeNode
        :rtype: int
        """
        if not root:
            return 0
        elif self.isLeaf(root.left):
            return root.left.val + self.sumOfLeftLeaves(root.right)
        else:
            return self.sumOfLeftLeaves(root.left) + self.sumOfLeftLeaves(root.right)

def isLeaf(self, node):
        if not node:
            return False
        if not node.left and not node.right:
            return True
        return False
```

Here is a step by step explanation of the code:

1. We define a class `Solution` with two methods: `sumOfLeftLeaves` and `isLeaf`.
2. `sumOfLeftLeaves` is the main function that takes the root of the binary tree as input and returns the sum of all left leaves.
3. If the root is `None`, we return 0 because there are no leaves in an empty tree.
4. If the left child of the root is a leaf node, we add its value to the sum of left leaves of the right subtree.
5. If the left child of the root is not a leaf node, we recursively find the sum of left leaves in the left and right subtrees.
6. `isLeaf` is a helper function that checks if a node is a leaf node. A node is a leaf node if it does not have any children. If the node is `None` or it has any child, it is not a leaf node.

Knowee AI · Accepted Answer

Sure, here is a Python solution for the problem:

```python
class Solution(object):
    def sumOfLeftLeaves(self, root):
        """
        :type root: TreeNode
        :rtype: int
        """
        if not root:
            return 0
        elif self.isLeaf(root.left):
            return root.left.val + self.sumOfLeftLeaves(root.right)
        else:
            return self.sumOfLeftLeaves(root.left) + self.sumOfLeftLeaves(root.right)

def isLeaf(self, node):
        if not node:
            return False
        if not node.left and not node.right:
            return True
        return False
```

Here is a step by step explanation of the code:

1. We define a class `Solution` with two methods: `sumOfLeftLeaves` and `isLeaf`.
2. `sumOfLeftLeaves` is the main function that takes the root of the binary tree as input and returns the sum of all left leaves.
3. If the root is `None`, we return 0 because there are no leaves in an empty tree.
4. If the left child of the root is a leaf node, we add its value to the sum of left leaves of the right subtree.
5. If the left child of the root is not a leaf node, we recursively find the sum of left leaves in the left and right subtrees.
6. `isLeaf` is a helper function that checks if a node is a leaf node. A node is a leaf node if it does not have any children. If the node is `None` or it has any child, it is not a leaf node.

Given the root of a binary tree, return the sum of all left leaves.A leaf is a node with no children. A left leaf is a leaf that is the left child of another node.

Question

Solution

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