LeetCode Sum of Left Leaves Explained - Java

Okay, let's reformat the explanation of the `sumOfLeftLeaves` code in the style you provided for the LeetCode problem.

*LeetCode (Not a specific LeetCode Problem, but similar in concept): Sum of Left Leaves in a Binary Tree*

* *Purpose:*
* The code aims to calculate the sum of the values of all *left leaf* nodes in a given binary tree.
* A left leaf is defined as a node that is the left child of its parent and has no children of its own (both left and right children are null).

* *Explanation:*

1. *Initialization:*
* `Queue(TreeNode) q`: A queue is used to perform a Breadth-First Search (BFS) traversal of the tree.
* `int ans = 0`: Stores the sum of the values of the left leaves.

2. *Initial Queue:*
* The root node of the tree is added to the queue to start the BFS.

3. *BFS Traversal:*
* The code enters a `while` loop that continues as long as the queue is not empty.
* A `for` loop iterates `size` times, processing each node at the current level.

4. *Node Processing:*
* *Left Child Check:*
* *Left Leaf Check:*
* *Right Child Processing:*

5. *Return Result:*
* After the BFS traversal is complete, the function returns the sum of the left leaf values (`ans`).

* *In simpler terms:*
The code explores the tree level by level. When it encounters a node, it checks if its *left* child is a leaf. If it is, the left child's value is added to the total sum. This process continues until all nodes have been visited.

* *Example:*

Consider the tree:

```
3
/ \
9 20
/ / \
15 17 7
```

* 15 is a left leaf (left child of 9, and has no children).
* 17 is a left leaf (left child of 20, and has no children).
* 7 is *not* a left leaf (it's a right child).

The code would return 15 + 17 = 32.

I hope this explanation is helpful! Let me know if you have any further questions.

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