feat: add javascript solution to lcci problem: No.17.10.Find Majority Element (doocs#371)

* 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

Author: zhaocchen

lcci/17.10.Find Majority Element/README.md

@@ -35,6 +35,8 @@
 
 <!-- 这里可写通用的实现逻辑 -->
 
+摩尔投票法
+
 <!-- tabs:start -->
 
 ### **Python3**
@@ -53,6 +55,31 @@
 
 ```
 
+### **JavaScript**
+
+```js
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var majorityElement = function(nums) {
+    let candidate = 0, count = 0;
+    for (let num of nums) {
+        if (count == 0) candidate = num;
+        if (candidate == num) {
+            count++;
+        } else {
+            count--;
+        }
+    }
+    let n = 0;
+    for (let num of nums) {
+        if (candidate == num) n++;
+    }
+    return n > (nums.length / 2) ? candidate : -1;
+};
+```
+
 ### **...**
 
 ```

lcci/17.10.Find Majority Element/README_EN.md

@@ -38,6 +38,8 @@
 
 ## Solutions
 
+Boyer–Moore majority vote algorithm
+
 <!-- tabs:start -->
 
 ### **Python3**
@@ -52,6 +54,31 @@
 
 ```
 
+### **JavaScript**
+
+```js
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var majorityElement = function(nums) {
+    let candidate = 0, count = 0;
+    for (let num of nums) {
+        if (count == 0) candidate = num;
+        if (candidate == num) {
+            count++;
+        } else {
+            count--;
+        }
+    }
+    let n = 0;
+    for (let num of nums) {
+        if (candidate == num) n++;
+    }
+    return n > (nums.length / 2) ? candidate : -1;
+};
+```
+
 ### **...**
 
 ```

lcci/17.10.Find Majority Element/Solution.js

@@ -0,0 +1,20 @@
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+ var majorityElement = function(nums) {
+    let candidate = 0, count = 0;
+    for (let num of nums) {
+        if (count == 0) candidate = num;
+        if (candidate == num) {
+            count++;
+        } else {
+            count--;
+        }
+    }
+    let n = 0;
+    for (let num of nums) {
+        if (candidate == num) n++;
+    }
+    return n > (nums.length / 2) ? candidate : -1;
+};