feat: add solution of Best Time to Buy and Sell Stock(121) with javascript.

Author: taryn2016

README.md

@@ -83,7 +83,7 @@
 | [112][112-question] | [Path Sum][112-tips]                                         | [Easy][E]   | [✅][112-java] | [✅][112-js] | [✅][112-kotlin] |
 | [118][118-question] | [Pascal's Triangle][118-tips]                                | [Easy][E]   | [✅][118-java] | [✅][118-js] | [✅][118-kotlin] |
 | [119][119-question] | [Pascal's Triangle II][119-tips]                             | [Easy][E]   | [✅][119-java] | [✅][119-js]| [✅][119-kotlin] |
-| [121][121-question] | [Best Time to Buy and Sell Stock][121-tips]                  | [Easy][E]   | [✅][121-java] |              | [✅][121-kotlin] |
+| [121][121-question] | [Best Time to Buy and Sell Stock][121-tips]                  | [Easy][E]   | [✅][121-java] | [✅][121-js]| [✅][121-kotlin] |
 | [122][122-question] | [Best Time to Buy and Sell Stock II][122-tips]               | [Easy][E]   | [✅][122-java] |              | [✅][122-kotlin] |
 | [125][125-question] | [Valid Palindrome][125-tips]                                 | [Easy][E]   |                |              | [✅][125-kotlin] |
 | [136][136-question] | [Single Number][136-tips]                                    | [Easy][E]   |                |              | [✅][136-kotlin] |
@@ -463,6 +463,7 @@ commit信息模板: ``feat: add the solution of `Two Sum`(001) with Java``
 [112-js]: ./src/_112/Solution.js
 [118-js]: ./src/_118/Solution.js
 [119-js]: ./src/_119/Solution.js
+[121-js]: ./src/_121/Solution.js
 [226-js]: ./src/_226/Solution.js
 [561-js]: ./src/_561/Solution.js
 [643-js]: ./src/_643/Solution.js

src/_121/Solution.js

@@ -0,0 +1,16 @@
+/**
+ * @param {number[]} prices
+ * @return {number}
+ */
+var maxProfit = function(prices) {
+  let finalProfit = 0
+  for(var i = 0; i < prices.length; i++) {
+      for(var j = 0; j < i; j++) {
+          let profit = prices[i] - prices[j]
+          if(profit > finalProfit) {
+              finalProfit = profit
+          }
+      }
+  }
+  return finalProfit
+};

tips/121/README.md

@@ -62,6 +62,20 @@ class Solution {
 }
 ```
 
+```JavaScript
+var maxProfit = function(prices) {
+  let finalProfit = 0
+  for(var i = 0; i < prices.length; i++) {
+      for(var j = 0; j < i; j++) {
+          let profit = prices[i] - prices[j]
+          if(profit > finalProfit) {
+              finalProfit = profit
+          }
+      }
+  }
+  return finalProfit
+};
+```
 ## 结语
 
 如果你同我们一样热爱数据结构、算法、LeetCode，可以关注我们 GitHub 上的 LeetCode 题解：[LeetCode-Solution][ls]