Merge pull request #3247 from winfred-lu/main

Create 0071-simplify-path.cpp

Author: sujal-goswami

Diff for: cpp/0071-simplify-path.cpp

@@ -0,0 +1,49 @@
+/*
+    Given an absolute path to a file or directory in a Unix-style file system,
+    convert it to the simplified canonical path.
+
+    In a Unix-style file system, a period '.' refers to the current directory.
+    A double period '..' refers to the directory up a level.
+    Any multiple consecutive slashes (i.e. '//') are treated as a single slash '/'.
+    For this problem, any other format of periods such as '...' are treated as file/directory names.
+
+    The canonical path should have the following format:
+    - The path starts with a single slash '/'.
+    - Any two directories are separated by a single slash '/'.
+    - The path does not end with a trailing '/'.
+    - The path only contains the directories on the path from the root directory to the target file or directory (i.e., no period '.' or double period '..')
+
+    Return the simplified canonical path.
+
+    Time: O(n)
+    Space: O(n)
+*/
+
+class Solution {
+public:
+    string simplifyPath(string path) {
+        stringstream ss(path);
+        string dir;
+        stack<string> stk;
+
+        while (getline(ss, dir, '/')) {
+            if (dir.empty() || dir == ".") {
+                continue;
+            }
+            else if (dir == "..") {
+                if (!stk.empty())
+                    stk.pop();
+            }
+            else {
+                stk.push(dir);
+            }
+        }
+
+        string res = "";
+        while (!stk.empty()) {
+            res = "/" + stk.top() + res;
+            stk.pop();
+        }
+        return res.empty()? "/" : res;
+    }
+};