#include <bits/stdc++.h>
using
namespace
std;
struct
Node {
int
data;
struct
Node* left, *right;
};
struct
Node* getNode(
int
data)
{
struct
Node* new_node =
(
struct
Node*)
malloc
(
sizeof
(
struct
Node));
new_node->data = data;
new_node->left = new_node->right = NULL;
return
new_node;
}
void
storeInorderTraversal(
struct
Node* root,
vector<
int
>& arr)
{
if
(!root)
return
;
storeInorderTraversal(root->left, arr);
arr.push_back(root->data);
storeInorderTraversal(root->right, arr);
}
void
replaceNodeWithSum(
struct
Node* root,
vector<
int
> arr,
int
* i)
{
if
(!root)
return
;
replaceNodeWithSum(root->left, arr, i);
root->data = arr[*i - 1] + arr[*i + 1];
++*i;
replaceNodeWithSum(root->right, arr, i);
}
void
replaceNodeWithSumUtil(
struct
Node* root)
{
if
(!root)
return
;
vector<
int
> arr;
arr.push_back(0);
storeInorderTraversal(root, arr);
arr.push_back(0);
int
i = 1;
replaceNodeWithSum(root, arr, &i);
}
void
preorderTraversal(
struct
Node* root)
{
if
(!root)
return
;
cout << root->data <<
" "
;
preorderTraversal(root->left);
preorderTraversal(root->right);
}
int
main()
{
struct
Node* root = getNode(1);
root->left = getNode(2);
root->right = getNode(3);
root->left->left = getNode(4);
root->left->right = getNode(5);
root->right->left = getNode(6);
root->right->right = getNode(7);
cout <<
"Preorder Traversal before tree modification:n"
;
preorderTraversal(root);
replaceNodeWithSumUtil(root);
cout <<
"\nPreorder Traversal after tree modification:n"
;
preorderTraversal(root);
return
0;
}