/**
* 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:
//先根序遍历二叉树，插入字符串，若数字为54，插入后变为“45#”
void preOrder(TreeNode* root, string& result){
if(root) {
int num = root->val;
while(num != 0){
//从低位到高位逆序插入字符串
result.push_back(num%10 +'0');
num = num/10;
}
result += '#';
preOrder(root->left, result);
preOrder(root->right, result);
}
}
// Encodes a tree to a single string.
string serialize(TreeNode* root) {
string result = "";
preOrder(root, result);
return result;
}
void insertNode(TreeNode* &root, int num){
//根为空，则创建新节点插入
if(root == NULL) {
//cout<< "insert";
root = new TreeNode(num);
return;
}
//大于根，则插入根的右子树
else if(num >= root->val){
//cout<< "num = "<< num<< " root="<<root->val<< " right"<<endl;
insertNode(root->right, num);
}
//小于根，则插入根的左子树
else {
//cout<< "num = "<< num<< " root="<<root->val<< " left"<<endl;
insertNode(root->left, num);
}
}
// Decodes your encoded data to tree.
TreeNode* deserialize(string data) {
TreeNode* root = NULL;
//cout << data <<" length="<<data.length()<< endl;
if(data.length() == 0) return root;
//count标记位数
int count = 0;
for(int i = 0; i< data.length(); i++ ){
int sum = 0;
//没遇到“#”则认为还是同一个数
while(data[i] != '#'){
int num = data[i]-'0';
//cout<< "data="<<data[i]<<" num="<< num<<" count="<<count<<endl;
for(int j = 0; j < count;j++){
//cout<< num<< endl;
//高位需乘10
num = num * 10;
}
count += 1;
sum += num;
i++;
}
//cout<<"push "<< sum<< endl;
count = 0;
insertNode(root, sum);
}return root;
}
};
// Your Codec object will be instantiated and called as such:
// Codec* ser = new Codec();
// Codec* deser = new Codec();
// string tree = ser->serialize(root);
// TreeNode* ans = deser->deserialize(tree);
// return ans;
