feat: add javascript solution to lcci problem: No.08.04, No.08.07 (doocs#375)

* 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

* feat: add javascript solution to lcci problem: No.17.10.Find Majority Element

* feat: add javascript solution to lcci problem: No.01.08.Zero Matrix

* chore: add development environment  start script

* feat: add javascript solution to lcci problem: No.01.07.Rotate Matrix

* feat: add javascript solution to lcci problem: No.08.04.Power Set

* feat: add javascript solution to lcci problem: No.08.07.Permutation I

Author: zhaocchen

lcci/08.04.Power Set/README.md

@@ -29,6 +29,8 @@
 
 <!-- 这里可写通用的实现逻辑 -->
 
+回溯法
+
 <!-- tabs:start -->
 
 ### **Python3**
@@ -47,6 +49,31 @@
 
 ```
 
+### **JavaScript**
+
+```js
+/**
+ * @param {number[]} nums
+ * @return {number[][]}
+ */
+var subsets = function(nums) {
+    let prev = [];
+    let res = [];
+    dfs(nums, 0, prev, res);
+    return res;
+};
+
+function dfs (nums, depth, prev, res) {
+    res.push(prev.slice());
+    for (let i = depth; i < nums.length; i++) {
+        prev.push(nums[i]);
+        depth++;
+        dfs(nums, depth, prev, res);
+        prev.pop();
+    }
+}
+```
+
 ### **...**
 
 ```

lcci/08.04.Power Set/README_EN.md

@@ -40,6 +40,8 @@
 
 ## Solutions
 
+Backtracking
+
 <!-- tabs:start -->
 
 ### **Python3**
@@ -54,6 +56,31 @@
 
 ```
 
+### **JavaScript**
+
+```js
+/**
+ * @param {number[]} nums
+ * @return {number[][]}
+ */
+var subsets = function(nums) {
+    let prev = [];
+    let res = [];
+    dfs(nums, 0, prev, res);
+    return res;
+};
+
+function dfs (nums, depth, prev, res) {
+    res.push(prev.slice());
+    for (let i = depth; i < nums.length; i++) {
+        prev.push(nums[i]);
+        depth++;
+        dfs(nums, depth, prev, res);
+        prev.pop();
+    }
+}
+```
+
 ### **...**
 
 ```

lcci/08.04.Power Set/Solution.js

@@ -0,0 +1,20 @@
+/**
+ * @param {number[]} nums
+ * @return {number[][]}
+ */
+ var subsets = function(nums) {
+    let prev = [];
+    let res = [];
+    dfs(nums, 0, prev, res);
+    return res;
+};
+
+function dfs (nums, depth, prev, res) {
+    res.push(prev.slice());
+    for (let i = depth; i < nums.length; i++) {
+        prev.push(nums[i]);
+        depth++;
+        dfs(nums, depth, prev, res);
+        prev.pop();
+    }
+}

lcci/08.07.Permutation I/README.md

@@ -32,6 +32,8 @@
 
 <!-- 这里可写通用的实现逻辑 -->
 
+回溯法
+
 <!-- tabs:start -->
 
 ### **Python3**
@@ -50,6 +52,40 @@
 
 ```
 
+### **JavaSript**
+
+```js
+/**
+ * @param {string} S
+ * @return {string[]}
+ */
+var permutation = function(S) {
+    let res = [];
+    let arr = [...S];
+    let prev = [];
+    let record = new Array(S.length).fill(false);
+    dfs(arr, 0, prev, record, res);
+    return res;
+};
+
+function dfs(arr, depth, prev, record, res) {
+    if (depth == arr.length) {
+        res.push(prev.join(''));
+        return;
+    }
+    for (let i = 0; i < arr.length; i++) {
+        if (record[i]) {
+            continue;
+        }
+        prev.push(arr[i]);
+        record[i] = true;
+        dfs(arr, depth + 1, prev, record, res);
+        prev.pop();
+        record[i] = false;
+    }
+}
+```
+
 ### **...**
 
 ```

lcci/08.07.Permutation I/README_EN.md

@@ -35,6 +35,8 @@
 
 ## Solutions
 
+Backtracking
+
 <!-- tabs:start -->
 
 ### **Python3**
@@ -49,6 +51,40 @@
 
 ```
 
+### **JavaSript**
+
+```js
+/**
+ * @param {string} S
+ * @return {string[]}
+ */
+var permutation = function(S) {
+    let res = [];
+    let arr = [...S];
+    let prev = [];
+    let record = new Array(S.length).fill(false);
+    dfs(arr, 0, prev, record, res);
+    return res;
+};
+
+function dfs(arr, depth, prev, record, res) {
+    if (depth == arr.length) {
+        res.push(prev.join(''));
+        return;
+    }
+    for (let i = 0; i < arr.length; i++) {
+        if (record[i]) {
+            continue;
+        }
+        prev.push(arr[i]);
+        record[i] = true;
+        dfs(arr, depth + 1, prev, record, res);
+        prev.pop();
+        record[i] = false;
+    }
+}
+```
+
 ### **...**
 
 ```

lcci/08.07.Permutation I/Solution.js

@@ -0,0 +1,29 @@
+/**
+ * @param {string} S
+ * @return {string[]}
+ */
+ var permutation = function(S) {
+    let res = [];
+    let arr = [...S];
+    let prev = [];
+    let record = new Array(S.length).fill(false);
+    dfs(arr, 0, prev, record, res);
+    return res;
+};
+
+function dfs(arr, depth, prev, record, res) {
+    if (depth == arr.length) {
+        res.push(prev.join(''));
+        return;
+    }
+    for (let i = 0; i < arr.length; i++) {
+        if (record[i]) {
+            continue;
+        }
+        prev.push(arr[i]);
+        record[i] = true;
+        dfs(arr, depth + 1, prev, record, res);
+        prev.pop();
+        record[i] = false;
+    }
+}