Leetcode 449. Serialize and Deserialize BST (Medium) (cpp)

Leetcode 449. Serialize and Deserialize BST (Medium) (cpp)

Tag: Tree

Difficulty: Medium

/*

449. Serialize and Deserialize BST (Medium)

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 search tree. There is no restriction on how your serialization/deserialization algorithm should work. You just need to ensure that a binary search tree can be serialized to a string and this string can be deserialized to the original tree structure.

The encoded string should be as compact as possible.

Note: Do not use class member/global/static variables to store states. Your serialize and deserialize algorithms should be stateless.

*/
/**
* 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:

// Encodes a tree to a single string.
string serialize(TreeNode* root) {
ostringstream out;
serialize(root, out);
return out.str();
}

// Decodes your encoded data to tree.
TreeNode* deserialize(string data) {
istringstream in(data);
return deserialize(in);
}
private:
void serialize(TreeNode* root, ostringstream& out) {
if (root) {
out << root->val << ' ';
serialize(root->left, out);
serialize(root->right, out);
}
else {
out << "# ";
}
}
TreeNode* deserialize(istringstream& in) {
string val;
in >> val;
if (val == "#")
return nullptr;
TreeNode* root = new TreeNode(stoi(val));
root->left = deserialize(in);
root->right = deserialize(in);
return root;
}
};
// Your Codec object will be instantiated and called as such:
// Codec codec;
// codec.deserialize(codec.serialize(root));