Simplify Path [LeetCode]

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

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

click to show corner cases.

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".

Summary: Very careful about corner cases, like "/", "/.", "..". 

 1 class Solution {

 2 public:

 3     void handleEntry(vector<string> &path_stack, string path_entry) {

 4         if(path_entry == "..") {

 5             if(path_stack.size() > 0)

 6                 path_stack.pop_back();

 7         }else if (path_entry != ".") 

 8                 path_stack.push_back(path_entry);

 9     }

10     

11     string simplifyPath(string path) {

12         string simple_path;

13         if(path.size() == 0)

14             return simple_path;

15         vector<string> path_stack;

16         string path_entry;

17         for(int i = 0; i < path.size(); i ++) {

18             if(path_entry.size() == 0 && path[i] == '/'){

19                 continue;

20             }else if (path_entry.size() != 0 && path[i] == '/') {

21                 handleEntry(path_stack, path_entry);

22                 path_entry.clear();

23             }else {

24                 path_entry.push_back(path[i]);

25             }

26         }

27         if(path_entry.size() > 0)

28             handleEntry(path_stack, path_entry);

29     

30         for(string item: path_stack) {

31             simple_path += "/";

32             simple_path += item;

33         }

34         if(simple_path.size() == 0)

35             return "/";

36         return simple_path;

37     }

38 };