# Sum of alternate leaf nodes in bst in c++

C++ program for Sum of alternate leaf nodes in bst. Here more information.

``````// Include header file
#include <iostream>
using namespace std;
// C++ program for
// Sum of alternate leaf nodes in bst
class TreeNode
{
public:
int data;
TreeNode *left;
TreeNode *right;
TreeNode(int data)
{
this->data = data;
this->left = nullptr;
this->right = nullptr;
}
};
class BinarySearchTree
{
public:
TreeNode *root;
bool alternate;
BinarySearchTree()
{
this->root = nullptr;
this->alternate = false;
}
// Insert a new node element
{
// Create a new node
TreeNode *node = new TreeNode(data);
if (this->root == nullptr)
{
// When add first node in bst
this->root = node;
}
else
{
TreeNode *find = this->root;
// Add new node to proper position
while (find != nullptr)
{
if (find->data >= data)
{
if (find->left == nullptr)
{
// When left child empty
// So add new node here
find->left = node;
return;
}
else
{
// Otherwise
// Visit to left sub-tree
find = find->left;
}
}
else
{
if (find->right == nullptr)
{
// When right child empty
// So add new node here
find->right = node;
return;
}
else
{
// Visit to right sub-tree
find = find->right;
}
}
}
}
}
int leafSum(TreeNode *node)
{
if (node != nullptr)
{
if (node->left == nullptr &&
node->right == nullptr)
{
// Case A
// When node is leaf node
// Change status
this->alternate = !this->alternate;
// Check node is alternate or not
if (this->alternate)
{
// When get alternate node
return node->data;
}
}
else
{
// Case B
// When node is internal
// Visit left and right subtree and find alternate node
return this->leafSum(node->left) +
this->leafSum(node->right);
}
}
return 0;
}
int alternateLeafSum()
{
// Reset alternate leaf node status
this->alternate = false;
return this->leafSum(this->root);
}
};
int main()
{
BinarySearchTree *tree = new BinarySearchTree();
/*
Binary search tree
-------------------
5
/  \
/    \
/      \
3        19
/ \     /   \
2   4   8     31
/ \    / \
7   15 25  50
*/
// Test
cout << tree->alternateLeafSum() << endl;
return 0;
}``````

Output

``34``

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