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：

1     string simplifyPath(string path) { 2         // IMPORTANT: Please reset any member data you declared, as 3         // the same Solution instance will be reused for each test case. 4         stack
     
       Stack; 5         while(true){ 6             if(path == "/") 7                 break; 8             int index = path.find('/', 1); 9             string tmp;10             if(index == -1){11                 tmp = path.substr(1);12                 path = "/";13             }14             else{15                 tmp = path.substr(1, index-1);16                 path = path.substr(index);17             }18             if(tmp == "")19                 continue;20             else if(tmp == ".."){21                 if(!Stack.empty())22                     Stack.pop();23                 else24                     continue;25             }26             else if(tmp != ".")   27                 Stack.push(tmp);28         }29         string result = "";30         if(Stack.empty())31             return "/";32         while(!Stack.empty()){33             result = "/" + Stack.top() + result;34             Stack.pop();35         }36         return result;37     }