Simplify Path

最新推荐文章于 2020-02-07 13:43:23 发布

IIcyZhao

最新推荐文章于 2020-02-07 13:43:23 发布

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分类专栏： LeetCode记录

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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".

class Solution {
public:
    string simplifyPath(string path) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        if (path.empty()) {
            return "";
        }
        deque<string> dq;
        char ch = ' ', pre = ' ';
        const char* p = path.c_str();
        string sub_path;
        ch = *p;
        
        if (ch == '/') {
          sub_path.push_back(ch);
          pre = ch;
          dq.push_back(sub_path);
          sub_path.clear();
        } 
        ++p;
        while (ch = *p) {
           if (ch == '/' && pre != '/') {
              if (sub_path == "\.") {
                ;
              } else if (sub_path == "\.\.") {
                  if (dq.back() != "/") {
                    dq.pop_back();
                  }
              } else {
                sub_path.push_back(ch);
                pre = ch;
                dq.push_back(sub_path);
              }
              pre = ch;
              sub_path.clear();
              ++p;
           } else if (ch == '/' && pre == '/') {
               ++p;
           } else {
              sub_path.push_back(ch);
              pre = ch;
              ++p;
           }
        }
        if (sub_path != "\." && sub_path != "\.\.") {
            dq.push_back(sub_path);
        } else if (sub_path == "\.\.") {
            if (dq.back() != "/") {
               dq.pop_back();
            }
        }
           
        string result;
        while (!dq.empty()) {
            result.append(dq.front());
               dq.pop_front();
        }
        if (result.size() > 1 && *result.rbegin() == '/') {
            return string(result.c_str(), result.size() -1);
        } else {
          return result;
        }
    }
};