//--------------------------------------------------------------------------------------------------
// Convert a given tree to a tree where every node contains sum of values of
// nodes in left and right subtrees in the original tree
int toSumTree(struct node *node)
{
// Base case
if(node == NULL)
return 0;
// Store the old value
int old_val = node->data;
// Recursively call for left and right subtrees and store the sum as new value of this node
node->data = toSumTree(node->left) + toSumTree(node->right);
// Return the sum of values of nodes in left and right subtrees and
// old_value of this node
return node->data + old_val;
}
/* Driver function to test above functions */
int main()
{
struct node *root = NULL;
int x;
/* Constructing tree given in the above figure */
root = newNode(10);
root->left = newNode(-2);
root->right = newNode(6);
root->left->left = newNode(8);
root->left->right = newNode(-4);
root->right->left = newNode(7);
root->right->right = newNode(5);
root->left->left->left = newNode(1);
//root->left->left->right = newNode(2);
//root->left->right->left = newNode(3);
//root->left->right->right = newNode(4);
toSumTree(root);
// Print inorder traversal of the converted tree to test result of toSumTree()
printf("Inorder Traversal of the resultant tree is: \n");
printInorder(root);
getchar();
return 0;
}
int toSumTree( Node * root )
{
if ( root == nullptr )
{
return 0;
}
//store the previous value
int previous_val = root->data;
// make current node as sum of left and right node. left nodes will become zero
root->data = toSumTree(root->left) + toSumTree(root->right);
// Now since each node contains the sum of the left and right sub trees in the original tree.
// we will return the sum of old + new value as sum.
// Focus on the world original here, and try understanding it from top to bottom.
return root->data + previous_val;
}
int main()
{
Node * root = new Node(10);
root->left = new Node(-2);
root->right = new Node(6);
root->left->left = new Node(8);
root->left->right = new Node(-4);
root->right->left = new Node(7);
root->right->right = new Node(5);
std::cout << "Inorder traversal of tree:";
inorder(root);
std::cout << "\nAfter transforming to sum tree\n";
toSumTree(root);
std::cout << "Inorder traversal of tree:";
inorder(root);
std::cout << std::endl;
return 0;
}
