feat: add question 122

Author: yinxin630

122.买卖股票的最佳时机-ii.js

@@ -0,0 +1,24 @@
+/*
+ * @lc app=leetcode.cn id=122 lang=javascript
+ *
+ * [122] 买卖股票的最佳时机 II
+ * 
+ * 1. 只要比前一天价格低, 就有差值可以赚
+ */
+
+// @lc code=start
+/**
+ * @param {number[]} prices
+ * @return {number}
+ */
+var maxProfit = function(prices) {
+    let result = 0;
+    for (let i = 1; i < prices.length; i++) {
+        if (prices[i] > prices[i - 1]) {
+            result += prices[i] - prices[i - 1];
+        }
+    }
+    return result;
+};
+// @lc code=end
+