Added solution

Author: avidLearnerInProgress

serialise_deserialise_bst.cpp

@@ -0,0 +1,56 @@
+/**
+ * Definition for a binary tree node.
+ * struct TreeNode {
+ *     int val;
+ *     TreeNode *left;
+ *     TreeNode *right;
+ *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
+ * };
+ */
+class Codec {
+public:
+    string serialize(TreeNode* root) {
+        ostringstream out;
+        serializeHelper(root, out);
+        return out.str();
+    }
+
+    // Decodes your encoded data to tree.
+    TreeNode* deserialize(string data) {
+        if(data.empty()) {
+            return NULL;
+        }
+        istringstream in(data);
+        queue<int> q;
+        string val;
+        while(in >> val) {
+            q.push(stoi(val));
+        }
+        return deserializeHelper(q, INT_MIN, INT_MAX);
+    }
+private:
+    void serializeHelper(TreeNode* root, ostringstream& out) {
+        if(root == NULL)
+            return;
+        out << root -> val << " ";
+        serializeHelper(root->left, out);
+        serializeHelper(root->right, out);
+    }
+    TreeNode* deserializeHelper(queue<int>& q, int lower, int upper) {
+        if(q.empty())
+            return NULL;
+        int cur = q.front();
+        if(cur < lower || cur > upper) {
+            return NULL;
+        }
+        TreeNode* root = new TreeNode(cur);
+        q.pop();
+        root -> left = deserializeHelper(q, lower, cur);
+        root -> right = deserializeHelper(q, cur, upper);
+        return root;
+    }
+};
+
+// Your Codec object will be instantiated and called as such:
+// Codec codec;
+// codec.deserialize(codec.serialize(root));