add: Simplify Path

Author: hijiangtao

README.md

@@ -33,6 +33,8 @@ This is the solutions collection of my LeetCode submissions, most of them are pr
 |54|[Spiral Matrix](https://leetcode.com/problems/spiral-matrix/) | [JavaScript](./src/spiral-matrix/res.js)|Medium|
 |66|[Plus One](https://leetcode.com/problems/plus-one/) | [JavaScript](./src/plus-one/res.js)|Easy|
 |69|[Sqrt(x)](https://leetcode.com/problems/sqrtx/) | [JavaScript](./src/sqrtx/res.js)|Easy|
+
+|71|[Simplify Path](https://leetcode.com/problems/simplify-path/) | [JavaScript](./src/simplify-path/res.js)|Medium|
 |73|[Set Matrix Zeroes](https://leetcode.com/problems/set-matrix-zeroes/) | [JavaScript](./src/set-matrix-zeroes/res.js)|Medium|
 |75|[Sort Colors](https://leetcode.com/problems/sort-colors/) | [JavaScript](./src/sort-colors/res.js)|Medium|
 |91|[Decode Ways](https://leetcode.com/problems/decode-ways/) | [JavaScript](./src/decode-ways/res.js)|Medium|

src/simplify-path/res.js

@@ -0,0 +1,27 @@
+/**
+ * res.js
+ * @authors Joe Jiang ([email protected])
+ * @date    2017-05-11 09:59:27
+ * 
+ * @param {string} path
+ * @return {string}
+ */
+let simplifyPath = function(path) {
+    let len = path.length,
+        res = [];
+    
+    for (let i=0; i<len;) {
+        let tmp = '';
+        while (path.charAt(i) === '/' && i<len) i++;
+        while (path.charAt(i) !== '/' && i<len) {
+            tmp += path.charAt(i);
+            i++;
+        }
+        
+        if (tmp === '..') res.pop();
+        else if (tmp !== '.' && tmp !== '') res.push(tmp);
+    }
+    
+    if (res.length === 0) return '/';
+    else return '/' + res.join('/');
+};