题解 | #序列化二叉树#

先序遍历序列化二叉树
struct TreeNode {
    int val;
    struct TreeNode *left;
    struct TreeNode *right;
    TreeNode(int x) :
            val(x), left(NULL), right(NULL) {
    }
};
*/
class Solution {
private:
    string s="";
    int cur=0;
public:
    void dfs(TreeNode *root){
        if(root==NULL)
        {
            s+="#,";
            return;
        }
            
        s+=to_string(root->val);
        s+=",";
        dfs(root->left);
        dfs(root->right);
    }
    char* Serialize(TreeNode *root) {    
        dfs(root);
        char *ret=new char[s.length()+1];
        strcpy(ret,s.c_str());
        return ret;
    }

    TreeNode* create_dfs(){
        if(cur>=s.size())
            return NULL;
        TreeNode* node=NULL;
        if(s[cur]=='#')
        {
            cur+=2;
            return node;
        }else{
            int num=0;
            while(s[cur]!=','){
                num=num*10+s[cur]-'0';
                cur++;
            }
            node=new TreeNode(num);
            cur++;
        }
        node->left=create_dfs();
        node->right=create_dfs();
        return node;
    }
    TreeNode* Deserialize(char *str) {
        string s=str;
        cout<<s<<endl;
        TreeNode* ans=NULL;
        ans=create_dfs();
        return ans;
    }
};