LeetCode 297. 二叉树的序列化与反序列化
原题链接
中等
作者:
大明湖的鱼
,
2021-01-30 00:43:16
,
所有人可见
,
阅读 352
/**
* 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) {
if(root == NULL) return "#_";
string res = to_string(root->val) + "_";
res += serialize(root->left);
res += serialize(root->right);
return res; //前序encode
}
// Decodes your encoded data to tree.
TreeNode* deserialize(string data) {
stringstream ss(data);
string item;
queue<string> q;
while(getline(ss,item,'_')){ //把istream中的字符读到iten中,遇到_停止
q.push(item);
}
return helper(q);
}
TreeNode* helper(queue<string>& q){
string val = q.front();
q.pop();
if(val == "#"){
return NULL;
}
TreeNode* head = new TreeNode(stoi(val));
head->left = helper(q);
head->right = helper(q);
return head; //前序建树
}
};
// Your Codec object will be instantiated and called as such:
// Codec ser, deser;
// TreeNode* ans = deser.deserialize(ser.serialize(root));