# Total sum except adjacent of a given node in a Binary Tree

Given a BT and a key Node, find the total sum in BT, except those Node which are adjacent to key Node.
Examples: ## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

1. Traverse the tree using pre-order.
2. If current node is adjacent to the key then do not add it to the final sum.
3. If current node is the key then do not add it’s children to the final sum.
4. If key is not present then return sum of all nodes.

## C++

 `// C++ program to find total sum except a given Node in BT ` `#include ` `using` `namespace` `std; ` ` `  `struct` `Node { ` `    ``int` `data; ` `    ``struct` `Node *left, *right; ` `}; ` ` `  `// insertion of Node in Tree ` `Node* getNode(``int` `n) ` `{ ` `    ``struct` `Node* root = ``new` `Node; ` `    ``root->data = n; ` `    ``root->left = NULL; ` `    ``root->right = NULL; ` `    ``return` `root; ` `} ` ` `  `// sum of all element except those which are adjecent to key Node ` `void` `find_sum(Node* root, ``int` `key, ``int``& sum, ``bool` `incl) ` `{ ` `    ``if` `(root) { ` `        ``if` `(incl) { ` `            ``sum += root->data; ` ` `  `            ``if` `(root->left && root->left->data == key) { ` `                ``sum -= root->data; ` `            ``} ` `            ``else` `if` `(root->right && root->right->data == key) { ` `                ``sum -= root->data; ` `            ``} ` `        ``} ` ` `  `        ``incl = root->data == key ? ``false` `: ``true``; ` `        ``find_sum(root->left, key, sum, incl); ` `        ``find_sum(root->right, key, sum, incl); ` `    ``} ` `} ` ` `  `// Driver code ` `int` `main() ` `{ ` `    ``struct` `Node* root = getNode(15); ` `    ``root->left = getNode(13); ` `    ``root->left->left = getNode(12); ` `    ``root->left->left->left = getNode(11); ` `    ``root->left->right = getNode(14); ` `    ``root->right = getNode(20); ` `    ``root->right->left = getNode(18); ` `    ``root->right->right = getNode(24); ` `    ``root->right->right->left = getNode(23); ` `    ``root->right->right->right = getNode(25); ` `    ``int` `key = 20; ` `    ``int` `sum = 0; ` `    ``find_sum(root, key, sum, ``true``); ` `    ``printf``(``"%d "``, sum); ` `    ``return` `0; ` `} `

## Java

 `// Java program to find total sum except a given Node in BT ` `import` `java.util.*; ` `class` `Node ` `{ ` `    ``int` `data; ` `    ``Node left, right; ` `     `  `    ``// insertion of Node in Tree ` `    ``Node(``int` `key) ` `    ``{ ` `        ``data = key; ` `        ``left = right = ``null``; ` `    ``} ` `} ` `class` `GFG ` `{ ` `    ``static` `class` `cal ` `   ``{ ` `      ``int` `sum = ``0``; ` `    ``} ` `     `  `    ``// sum of all element except those which are adjecent to key Node ` `    ``public` `static` `void` `find_sum(Node root, ``int` `key, cal r, ``boolean` `incl) ` `    ``{ ` `        ``if``(root != ``null``) ` `        ``{ ` `            ``if``(incl == ``true``) ` `            ``{ ` `                ``r.sum += root.data; ` `                ``if``((root.left != ``null``) && (root.left.data == key)) ` `                        ``{ ` `               ``r.sum -= root.data; ` `            ``} ` `                 ``else`  `                 ``if``((root.right != ``null``) && (root.right.data == key)) ` `                       ``{ ` `                   ``r.sum -= root.data; ` `            ``} ` `                 `  `            ``} ` `             `  `            ``if``(root.data == key) ` `                ``incl = ``false``; ` `                ``else` `                ``incl = ``true``; ` `                 `  `        ``find_sum(root.left, key, r, incl); ` `        ``find_sum(root.right, key, r, incl); ` `        ``} ` `    ``} ` `     `  `// Driver code ` `public` `static` `void` `main (String[] args)  ` `{ ` `        ``Node root = ``new` `Node(``15``); ` `        ``root.left = ``new` `Node(``13``); ` `        ``root.left.left = ``new` `Node(``12``); ` `        ``root.left.left.left = ``new` `Node(``11``); ` `        ``root.left.right = ``new` `Node(``14``); ` `        ``root.right = ``new` `Node(``20``); ` `        ``root.right.left = ``new` `Node(``18``); ` `        ``root.right.right = ``new` `Node(``24``); ` `        ``root.right.right.right = ``new` `Node(``25``); ` `        ``root.right.right.left = ``new` `Node(``23``); ` `        ``int` `key = ``20``; ` `         ``cal obj = ``new` `cal(); ` `        ``find_sum(root, key, obj, ``true``); ` `        ``System.out.print(obj.sum); ` `    ``} ` `     `  `} `

## C#

 `// C# program to find total sum  ` `// except a given Node in BT  ` `using` `System; ` ` `  `public` `class` `Node ` `{ ` `    ``public` `int` `data; ` `    ``public` `Node left, right; ` `     `  `    ``// insertion of Node in Tree ` `    ``public` `Node(``int` `key) ` `    ``{ ` `        ``data = key; ` `        ``left = right = ``null``; ` `    ``} ` `} ` `public` `class` `GFG ` `{ ` `public` `class` `cal ` `{ ` `    ``public` `int` `sum = 0; ` `    ``} ` `     `  `    ``// sum of all element except those ` `    ``// which are adjecent to key Node ` `    ``public` `static` `void` `find_sum(Node root,  ` `                    ``int` `key, cal r, ``bool` `incl) ` `    ``{ ` `        ``if``(root != ``null``) ` `        ``{ ` `            ``if``(incl == ``true``) ` `            ``{ ` `                ``r.sum += root.data; ` `                ``if``((root.left != ``null``) &&  ` `                    ``(root.left.data == key)) ` `                ``{ ` `                    ``r.sum -= root.data; ` `                ``} ` `                ``else` `                ``if``((root.right != ``null``) && ` `                    ``(root.right.data == key)) ` `                ``{ ` `                    ``r.sum -= root.data; ` `                ``} ` `                 `  `            ``} ` `             `  `            ``if``(root.data == key) ` `                ``incl = ``false``; ` `            ``else` `                ``incl = ``true``; ` `                 `  `        ``find_sum(root.left, key, r, incl); ` `        ``find_sum(root.right, key, r, incl); ` `        ``} ` `    ``} ` `     `  `// Driver code ` `public` `static` `void` `Main (String[] args)  ` `{ ` `        ``Node root = ``new` `Node(15); ` `        ``root.left = ``new` `Node(13); ` `        ``root.left.left = ``new` `Node(12); ` `        ``root.left.left.left = ``new` `Node(11); ` `        ``root.left.right = ``new` `Node(14); ` `        ``root.right = ``new` `Node(20); ` `        ``root.right.left = ``new` `Node(18); ` `        ``root.right.right = ``new` `Node(24); ` `        ``root.right.right.right = ``new` `Node(25); ` `        ``root.right.right.left = ``new` `Node(23); ` `        ``int` `key = 20; ` `        ``cal obj = ``new` `cal(); ` `        ``find_sum(root, key, obj, ``true``); ` `        ``Console.Write(obj.sum); ` `    ``} ` `} ` ` `  `// This code is contributed Rajput-Ji  `

Output:

```118
```

Time Complexity : O(n) where n is number of nodes in the BT.

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