Added serialize and deserialize binary tree program in cpp

Code/C++/serialize_and_deserialize_binary_tree.cpp

@@ -0,0 +1,105 @@
+// Serialization is the process of converting a data structure or object into 
+// a sequence of bits so that it can be stored in a file or memory buffer, or 
+// transmitted across a network connection link to be reconstructed later in 
+// the same or another computer environment.
+// Design an algorithm to serialize and deserialize a binary tree. 
+
+#include <bits/stdc++.h>
+using namespace std; 
+
+struct node{ 
+    int next; 
+    struct node* left, *right; 
+}; 
+
+node* newNode(int next){ 
+    node* temp = new node; 
+    temp->next = next; 
+    temp->left = temp->right = NULL; 
+    return (temp); 
+} 
+
+// This function stores a tree in a file
+void serialize(node *root, FILE *f){
+    if(root == NULL){ 
+        fprintf(f, "%d ", -1); 
+        return; 
+    } 
+
+    // Else, store current node and call function for it's children
+    fprintf(f, "%d ", root->next); 
+    serialize(root->left, f); 
+    serialize(root->right, f); 
+} 
+
+// This function constructs a tree from a file
+void deserialize(node *&root, FILE *f){ 
+    // Read next item from file. If theere are no more items
+    // item is -1, then return 
+    int val; 
+    if(!fscanf(f, "%d ", &val) || val == -1)
+       return; 
+
+    // Else create node with this item and call function for it's children 
+    root = newNode(val); 
+    deserialize(root->left, f); 
+    deserialize(root->right, f); 
+} 
+
+// A simple inorder traversal used for testing the constructed tree 
+void inorder(node *root){ 
+    if(root){ 
+        inorder(root->left); 
+        cout<<root->next<<" "; 
+        inorder(root->right); 
+    } 
+}
+int main(){ 
+    struct node *root        = newNode(14); 
+    root->left               = newNode(7); 
+    root->right              = newNode(21); 
+
+    //serialize the tree into the file 
+    FILE *f = fopen("tree.txt", "w"); 
+    if(f == NULL){ 
+        cout<<"Could not open file"; 
+        return 0; 
+    } 
+    serialize(root, f); 
+    fclose(f); 
+
+    // deserialize the storeed tree
+    node *root1 = NULL; 
+    f = fopen("tree.txt", "r"); 
+    deserialize(root1, f); 
+    inorder(root1); 
+
+    return 0; 
+}
+
+// output : 7 14 21
+
+// Test Cases :
+
+// Input: root = [1,2,3,null,null,4,5]
+// Output: [1,2,3,null,null,4,5]
+
+// Input: root = []
+// Output: []
+
+// Input: root = [1]
+// Output: [1]
+
+// Input: root = [1,2]
+// Output: [1,2]
+
+
+
+// Time complexity : In both serialization and deserialization functions, 
+//                   we visit each node exactly once, thus the time complexity is O(N),
+//                   where N is the number of nodes, i.e. the size of tree.
+
+// Space complexity : In both serialization and deserialization functions, 
+//                    we keep the entire tree, either at the beginning or at the end,
+//                    therefore, the space complexity is O(N).
+

Tree/readme.md

@@ -78,6 +78,7 @@ that, this property should be satisfied at every node in the tree.
 * Spiral Traversal of Binary Tree ----> [C++](/Code/C++/spiral_traversal_of_binary_tree.cpp) 
 * Distance between two nodes of a binary tree ----> [C++](/Code/C++/distance_between_two_nodes_of_BT.cpp)
 * Searching in BST ----> [C++](/Code/C++/searching_in_bst.cpp) | [Java](Code\Java\Searching_in_BST.Java)
+* Serialize and Deserialize Binary Tree ----> [C++](/Code/C++/serialize_and_deserialize_binary_tree.cpp)
 * Threaded Tree ----> [C++](/Code/C++/threaded_binary_tree.cpp) 
 * Top-View of a Binary tree ----> [C++](/Code/C++/Top-View.cpp)