Given an absolute path for a file (Unix-style), simplify it.

class Solution {

public:

    /**

     * @param path the original path

     * @return the simplified path

     */

    string simplifyPath(string& path) {

        int left = , right = , n = path.size();

        stack<string> s;

        string res = "";

        while (right < n) {

            while (left < n && path[left] == '/') ++left;

            right = left;

            while (right < n && path[right] != '/') ++right;

            string t = path.substr(left, right - left);

            if (t == "..") {

                if (!s.empty()) s.pop();

            } else if (t != ".") {

                if (!t.empty()) s.push(t);

            }

            left = right;

        }

        while (!s.empty()) {

            res = "/" + s.top() + res; s.pop();

        }

        return res.empty() ? "/" : res;

    }

};

class Solution {

public:

    /**

     * @param path the original path

     * @return the simplified path

     */

    string simplifyPath(string& path) {

        string res, t;

        stringstream ss(path);

        vector<string> v;

        while (getline(ss, t, '/')) {

            if (t == "" || t == ".") continue;

            if (t == ".." && !v.empty()) v.pop_back();

            else if (t != "..") v.push_back(t);

        }

        for (string s : v) res += "/" + s;

        return res.empty() ? "/" : res;

    }

};