Serialize and Deserialize Binay Tree solution

Author: PDKhan

serialize-and-deserialize-binary-tree/PDKhan.cpp

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+class Codec {
+public:
+    // Encodes a tree to a single string.
+    string serialize(TreeNode* root) {
+        string result;
+
+        if(root == nullptr)
+            return result;
+
+        queue<TreeNode*> q;
+
+        q.push(root);
+
+        while(!q.empty()){
+            TreeNode* curr = q.front();
+
+            q.pop();
+
+            if(curr){
+                result += to_string(curr->val) + ",";
+                q.push(curr->left);
+                q.push(curr->right);
+            }else{
+                result += "NULL,";
+            }
+        }
+
+        return result;
+    }
+    // Decodes your encoded data to tree.
+    TreeNode* deserialize(string data) {
+        if(!data.size())
+            return nullptr;
+        
+        queue<TreeNode*> q;
+        vector<string> values;
+        size_t prev = 0;
+        size_t pos = data.find(",", prev);
+
+        while(pos != string::npos){
+            values.push_back(data.substr(prev, pos - prev));
+            prev = pos + 1;
+            pos = data.find(",", prev);
+        }
+
+        int idx = 0;
+        TreeNode* root = new TreeNode(stoi(values[idx++]));
+        q.push(root);
+
+        while(!q.empty()){
+            int left = idx++;
+            int right = idx++;
+            TreeNode* curr = q.front();
+            q.pop();
+
+            if(left < values.size() && values[left] != "NULL"){
+                curr->left = new TreeNode(stoi(values[left]));
+                q.push(curr->left);
+            }
+            
+            if(right < values.size() && values[right] != "NULL"){
+                curr->right = new TreeNode(stoi(values[right]));
+                q.push(curr->right);
+            }
+        }
+
+        return root;
+    }
+};