Boundary Nodes Sum.txt

static void LeftBoundary(Node root)  
{  
    if (root != null) 
    {  
        if (root.left != null) 
        {  
            sum_of_boundary_nodes += root.data;  
            LeftBoundary(root.left);  
        }  
        else if (root.right != null) 
        {  
            sum_of_boundary_nodes += root.data;  
            LeftBoundary(root.right);  
        }  
    }  
}  
  
// Function to sum up all the right boundary nodes  
// except the leaf nodes  
static void RightBoundary(Node root)  
{  
    if (root != null) 
    {  
        if (root.right != null) 
        {  
            RightBoundary(root.right);  
            sum_of_boundary_nodes += root.data;  
        }  
        else if (root.left != null) 
        {  
            RightBoundary(root.left);  
            sum_of_boundary_nodes += root.data;  
        }  
    }  
}  
  
// Function to sum up all the leaf nodes  
// of a binary tree  
static void Leaves(Node root)  
{  
    if (root != null) 
    {  
        Leaves(root.left);  
  
        // Sum it up if it is a leaf node  
        if ((root.left == null) && (root.right == null))  
            sum_of_boundary_nodes += root.data;  
  
        Leaves(root.right);  
    }  
}  
  
// Function to return the sum of all the  
// boundary nodes of the given binary tree  
static int sumOfBoundaryNodes( Node root)  
{  
    if (root != null)  
    {  
  
        // Root node is also a boundary node  
        sum_of_boundary_nodes = root.data;  
  
        // Sum up all the left nodes  
        // in TOP DOWN manner  
        LeftBoundary(root.left);  
  
        // Sum up all the  
        // leaf nodes  
        Leaves(root.left);  
        Leaves(root.right);  
  
        // Sum up all the right nodes  
        // in BOTTOM UP manner  
        RightBoundary(root.right);  
  
        // Return the sum of  
        // all the boundary nodes  
        return sum_of_boundary_nodes;  
    }  
  
    return 0;  
}