71. Simplify Path

Author: NilStack

README.md

@@ -7,6 +7,7 @@ Not only Leetcode solutions in Swift.
 * [16. 3Sum Closest](https://leetcode.com/problems/3sum-closest/)
 * [18. 4Sum](https://leetcode.com/problems/4sum/)
 * [46. Group Anagrams](https://leetcode.com/problems/anagrams/)
+* [71. Simplify Path](https://leetcode.com/problems/simplify-path/)
 * [134. Gas Station](https://leetcode.com/problems/gas-station/)
 * [167. Two Sum II - Input array is sorted](https://leetcode.com/problems/two-sum-ii-input-array-is-sorted/)
 * [170. Two Sum III - Data structure design](https://leetcode.com/problems/two-sum-iii-data-structure-design)

SwiftyLeetCode.playground/Contents.swift

@@ -227,6 +227,55 @@ extension Solution {
 let groupAnagramsStrs = ["eat", "tea", "tan", "ate", "nat", "bat"]
 Solution.groupAnagrams(strs: groupAnagramsStrs)
 
+/**
+ * Question: 71. Simplify Path
+ * Link:  https://leetcode.com/problems/simplify-path/
+ * Author: Peng
+ */
+
+extension Solution {
+    class func simplifyPath(path: String?) -> String? {
+        guard let path = path, path.characters.count > 0 else {
+            return nil
+        }
+        
+        var result = "/"
+        let stubs = path.components(separatedBy: "/")
+        var paths = [String]()
+        
+        stubs.forEach { str in
+            if (str == "..") {
+                if (paths.count > 0) {
+                    paths.remove(at: paths.count - 1)
+                }
+            } else if (str != "." && str != "") {
+                paths.append(str)
+            }
+        }
+        
+        paths.forEach { path in
+            result += path + "/"
+        }
+        
+        let resultLength = result.characters.count
+        let index = result.index(result.startIndex, offsetBy: resultLength - 1)
+
+        if (resultLength > 1) {
+            result = result.substring(to: index)
+        }
+        
+        return result
+    }
+}
+
+// usage
+
+let path1 = "/home/"
+let path2 = "/a/./b/../../c/"
+
+Solution.simplifyPath(path: path1)
+Solution.simplifyPath(path: path2)
+
 /**
  * 134. Gas Station
  * https://leetcode.com/problems/gas-station/