Simplify Path

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

For example,
path = "/home/", => "/home"
path = "/a/./b/../../c/", => "/c"

Corner Cases:

• Did you consider the case where path = "/../"?
  In this case, you should return "/".
• Another corner case is the path might contain multiple slashes '/' together, such as "/home//foo/".
  In this case, you should ignore redundant slashes and return "/home/foo".

思路：

用一个栈来实现，对特殊情况进行判断

代码：

    string simplifyPath(string path) {
        // IMPORTANT: Please reset any member data you declared, as
        // the same Solution instance will be reused for each test case.
        stack<string> Stack;
        while(true){
            if(path == "/")
                break;
            int index = path.find('/', 1);
            string tmp;
            if(index == -1){
                tmp = path.substr(1);
                path = "/";
            }
            else{
                tmp = path.substr(1, index-1);
                path = path.substr(index);
            }
            if(tmp == "")
                continue;
            else if(tmp == ".."){
                if(!Stack.empty())
                    Stack.pop();
                else
                    continue;
            }
            else if(tmp != ".")   
                Stack.push(tmp);
        }
        string result = "";
        if(Stack.empty())
            return "/";
        while(!Stack.empty()){
            result = "/" + Stack.top() + result;
            Stack.pop();
        }
        return result;
    }