class Solution {
public:
    string simplifyPath(string path) {
        int N=path.size();
        stack<string> s;
        for(int i=0;i<N;)
        {
            while(i<N&&path[i]=='/')   //遇到/跳过
                i++;
            string temp="";           //记录字符串
            while(i<N&&path[i]!='/')
            {
                temp.push_back(path[i]);
                i++;
            }
            if(temp==".."&&s.empty()==0)
                s.pop();
            else if(temp!=""&&temp!=".."&&temp!=".")
                s.push(temp);
        }
        if(s.empty())   
            return "/";
        string res=""; 
        while(!s.empty())
        {
            res="/"+s.top()+res;
            s.pop();
        }
        return res;
    }
};