Problem_STOII_0048_Codec.cc

#include <iostream>
#include <list>
#include <string>
#include <vector>

using namespace std;

struct TreeNode
{
  int val;
  TreeNode *left;
  TreeNode *right;
  TreeNode(int x) : val(x), left(NULL), right(NULL) {}
};

class Codec
{
 public:
  void rseralize(TreeNode *root, string &str)
  {
    if (root == nullptr)
    {
      str += "Null,";
    }
    else
    {
      str += to_string(root->val) + ",";
      rseralize(root->left, str);
      rseralize(root->right, str);
    }
  }

  // Encodes a tree to a single string.
  string serialize(TreeNode *root)
  {
    string ans;
    rseralize(root, ans);
    return ans;
  }

  TreeNode *rdeserialize(list<string> &dataArray)
  {
    if (dataArray.front() == "Null")
    {
      dataArray.erase(dataArray.begin());
      return nullptr;
    }

    TreeNode *root = new TreeNode(stoi(dataArray.front()));
    dataArray.erase(dataArray.begin());
    root->left = rdeserialize(dataArray);
    root->right = rdeserialize(dataArray);
    return root;
  }

  // Decodes your encoded data to tree.
  TreeNode *deserialize(string data)
  {
    list<string> dataArray;
    string str;
    for (auto &ch : data)
    {
      if (ch == ',')
      {
        dataArray.push_back(str);
        str.clear();
      }
      else
      {
        str.push_back(ch);
      }
    }
    if (!str.empty())
    {
      dataArray.push_back(str);
      str.clear();
    }
    return rdeserialize(dataArray);
  }
};

// Your Codec object will be instantiated and called as such:
// Codec ser, deser;
// TreeNode* ans = deser.deserialize(ser.serialize(root));