Transform Binary tree to Sum tree

Author: TonyStark-19

Tree/TransfromToSumTree.cpp

@@ -0,0 +1,96 @@
+#include <iostream>
+#include <vector>
+using namespace std;
+
+// Node class
+class Node
+{
+public:
+    int data;
+    Node *left;
+    Node *right;
+
+    Node(int val)
+    {
+        data = val;
+        left = right = NULL;
+    }
+};
+
+static int idx = -1;
+Node *buildTree(vector<int> preorder)
+{
+    idx++;
+
+    // base case
+    if (preorder[idx] == -1)
+    {
+        return NULL;
+    }
+
+    // create root node
+    Node *root = new Node(preorder[idx]);
+
+    // left sub tree recursion call
+    root->left = buildTree(preorder);
+
+    // right sub tree recursion call
+    root->right = buildTree(preorder);
+
+    return root;
+}
+
+void preOrder(Node *root)
+{
+    // base case
+    if (root == NULL)
+    {
+        return;
+    }
+
+    cout << root->data << " ";
+
+    // left sub tree recursion call
+    preOrder(root->left);
+
+    // right sub tree recursion call
+    preOrder(root->right);
+}
+
+// transform to Sum tree
+int sumTree(Node *root)
+{
+    // base case
+    if (root == NULL)
+    {
+        return 0;
+    }
+
+    // left sub tree call
+    int leftSum = sumTree(root->left);
+
+    // right subtree call
+    int rightSum = sumTree(root->right);
+
+    root->data += leftSum + rightSum;
+
+    return root->data;
+}
+
+int main()
+{
+    vector<int> preorder = {1, 2, -1, -1, 3, 4, -1, -1, 5, -1, -1};
+    Node *root = buildTree(preorder);
+
+    cout << "before conversion: ";
+    preOrder(root);
+    cout << endl;
+
+    sumTree(root);
+
+    cout << "after conversion: ";
+    preOrder(root);
+    cout << endl;
+
+    return 0;
+}