add: Restore IP Addresses

Author: hijiangtao

README.md

@@ -33,11 +33,11 @@ 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|
+|93|[Restore IP Addresses](https://leetcode.com/problems/restore-ip-addresses/) | [JavaScript](./src/restore-ip-addresses/res.js)|Medium|
 |120|[Triangle](https://leetcode.com/problems/triangle/) | [JavaScript](./src/triangle/res.js)|Medium|
 |130|[Surrounded Regions](https://leetcode.com/problems/surrounded-regions/) | [JavaScript](./src/surrounded-regions/res.js)|Medium|
 |133|[Clone Graph](https://leetcode.com/problems/clone-graph/) | [JavaScript](./src/clone-graph/res.js)|Medium|

src/restore-ip-addresses/res.js

@@ -0,0 +1,43 @@
+/**
+ * res.js
+ * @authors Joe Jiang (hijiangtao@gmail.com)
+ * @date    2017-05-11 10:39:29
+ * 
+ * @param {string} s
+ * @return {string[]}
+ */
+let restoreIpAddresses = function(s) {
+    let len = s.length,
+        res = [];
+    if (len < 4) return [];
+
+    for (let first = 1; first < 5; first++) {
+        if (first === len) break;
+        for (let second = 1; second < 5; second++) {
+            if (first + second === len) break;
+            for (let third = 1; third < 5; third++) {
+                if (first + second + third === len) break;
+                let tmp1 = s.substring(0, first),
+                    tmp2 = s.substring(first, first + second),
+                    tmp3 = s.substring(first + second, first + second + third),
+                    tmp4 = s.substring(first + second + third);
+
+                if (isValid(tmp1) && isValid(tmp2) && isValid(tmp3) && isValid(tmp4)) {
+                    res.push(`${tmp1}.${tmp2}.${tmp3}.${tmp4}`);
+                }
+            }
+        }
+    }
+
+    return res;
+
+    function isValid(str) {
+        if (str.charAt(0) === '0' && str.length > 1) return false;
+
+        let num = Number.parseInt(str);
+        if (num < 256)
+            return true;
+        else
+            return false;
+    }
+};