学步园

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

For example,
path = "/home/", => "/home"

path = "/a/./b/../../c/", => "/c"

思路：

其实就是一个依次处理以'/'为分割的数据的工具。如果碰到空输入或者'.'就什么都不做，如果碰到".."就从队列里退出一个元素。最后将队列里的元素用'/'链接即可。

题解：

class Solution {
public:
    string simplifyPath(string path) {
        list<string> path_queue;
        
        string current_path;
        
        // ensure committing the last token
        path += '/';
        
        // iterate every character
        for(size_t i = 0; i < path.size(); ++i)
        {
            char ch = path[i];
            if (ch == '/')  // met splitter
            {
                if (current_path == "." || current_path == "")
                    ;// do nothing
                else if (current_path == "..")
                {   // pop last path
                    if (!path_queue.empty())
                        path_queue.pop_back();
                }
                else
                    path_queue.push_back(current_path);
                current_path = "";
            }
            else
                current_path += ch;
        }

        string ret;
        for(auto i : path_queue)
            if (i != "")
                ret += string("/") + i;
        if (ret == "")
            ret = "/";
        return ret;
    }
};