feat: add javascript solution to lcci problem: No.17.04.Missing Number (#369)

* feat: add javascript solution to lcci problem: No.02.01.Remove Duplicate Node

* feat: add javascript solution to lcci problem: No.02.02.Kth Node From End of List

* feat: add javascript solution to lcci problem: No.02.03.Delete Middle Node

* feat: add javascript solution to lcci problem: No.17.04.Missing Number

Author: zhaocchen

lcci/17.04.Missing Number/README.md

@@ -63,6 +63,22 @@ class Solution {
 }
 ```
 
+### **JavaScript**
+
+```js
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var missingNumber = function(nums) {
+    let res;
+    for (let i = 0; i < nums.length; i++) {
+        res = res ^ nums[i] ^ (i + 1);
+    }
+    return res;
+};
+```
+
 ### **...**
 
 ```

lcci/17.04.Missing Number/README_EN.md

@@ -61,6 +61,22 @@ class Solution {
 }
 ```
 
+### **JavaScript**
+
+```js
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var missingNumber = function(nums) {
+    let res;
+    for (let i = 0; i < nums.length; i++) {
+        res = res ^ nums[i] ^ (i + 1);
+    }
+    return res;
+};
+```
+
 ### **...**
 
 ```

lcci/17.04.Missing Number/Solution.js

@@ -0,0 +1,11 @@
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+ var missingNumber = function(nums) {
+    let res;
+    for (let i = 0; i < nums.length; i++) {
+        res = res ^ nums[i] ^ (i + 1);
+    }
+    return res;
+};