private static void PreOrder(LeetCode404TreeNode root, LeetCode404TreeNode parent)
{
if (root == null)
{
return;
}
if (root.IsLeavesNode() && root == parent.left)
{
sum += root.val;
}
else
{
PreOrder(root.left, root);
PreOrder(root.right, root);
}
}
public LeetCode404TreeNode(int val = 0, LeetCode404TreeNode left = null, LeetCode404TreeNode right = null)
{
this.val = val;
this.left = left;
this.right = right;
}
public static int SumLeftLeaves(LeetCode404TreeNode root)
{
PreOrder(root, root);
return(sum);
}
