二叉树序列化和反序列化（bfs），和leetcode一致

/**
 * 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) return "[]";
        string res="[";
        queue<TreeNode*> q;
        q.push(root);
        res+=myitos(root->val);
        res+=',';
        while(!q.empty()){
            root = q.front();
            q.pop();
            if(root->left){
                res+=myitos(root->left->val);
                q.push(root->left);
            }else
                res+="null";
            res+=',';
            if(root->right){
                 res+=myitos(root->right->val);
                 q.push(root->right);
            }else
                res+="null";
            res+=','; 
        }
        int i=res.size()-1;
        for(;i>=0;i--){
            if(isdigit(res[i]))
                break;
        }
        res=res.substr(0,i+1);
        res+=']';
        return res;
    }

    // Decodes your encoded data to tree.
    TreeNode* deserialize(string data) {
        if(data.size()==2) return NULL;
        queue<TreeNode*> q;
        queue<TreeNode*> cur;
        for(int i=1;i<data.size()-1;){
            for(int j=i;j<data.size();j++){
                if(data[j]==',' || data[j]==']'){
                    TreeNode *temp=NULL;
                    if(isdigit(data[i])) {
                        int sum=0;
                        for(int k=i;k<=j-1;k++){
                            sum = sum*10+(data[k]-48);
                        }
                        temp = new TreeNode(sum);
                    }
                    if(data[i]=='-') {
                        int sum=0;
                        for(int k=i+1;k<=j-1;k++){
                            sum = sum*10+(data[k]-48);
                        }
                        temp = new TreeNode(-sum);
                    }
                    q.push(temp);
                    i=j+1;
                    break;
                }
            }
        }              
        cur.push(q.front());q.pop();
        TreeNode *root=cur.front();
        while(!cur.empty()){
            if(q.empty()) return root;
            TreeNode *temp=cur.front();cur.pop();
            TreeNode *l =q.front();q.pop();
            TreeNode *r=NULL;
            if(!q.empty()) {
                r=q.front();
                q.pop();
            }
            temp->left =l;
            temp->right=r;
            if(l)
               cur.push(l);
            if(r)
                cur.push(r);
        }
        return root;
    }
    string myitos(int temp){
        string t="";
        if(temp<0){
            t+='-';
            temp=-temp;
        }
        string i="";
        do{
            i+=temp%10 + 48;
            temp/=10;
        }while(temp);
        reverse(i.begin(),i.end());
        t+=i;
        return t;
    }
};
//能写的这么长也算是前无古人后无来者了吧，，，，纪念下首次超100行的leetcode代码。。。。。
// Your Codec object will be instantiated and called as such:
// Codec codec;
// codec.deserialize(codec.serialize(root));```