Update.买卖股票的最佳时机2，添加C#

problems/0122.买卖股票的最佳时机II.md

@@ -406,6 +406,21 @@ object Solution {
   }
 }
 ```
+### C#
+```csharp
+public class Solution
+{
+    public int MaxProfit(int[] prices)
+    {
+        int res = 0;
+        for (int i = 0; i < prices.Length - 1; i++)
+        {
+            res += Math.Max(0, prices[i + 1] - prices[i]);
+        }
+        return res;
+    }
+}
+```
 
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