Add peoblem 121 .

1 files changed, 24 insertions, 0 deletions

diff --git a/cpp/121.cpp b/cpp/121.cpp
new file mode 100644
index 0000000..cba465d
--- /dev/null
+++ b/cpp/121.cpp
@@ -0,0 +1,24 @@
+#include <vector>
+
+using std::vector;
+
+class Solution
+{
+public:
+    int maxProfit(vector<int> &prices)
+    {
+        if (prices.size() <= 1) return 0;
+
+        int result = 0;
+        int min = prices.front();
+        for (int i = 1; i < prices.size(); i++)
+        {
+            if (prices[i] - min > result)
+                result = prices[i] - min;
+            if (prices[i] < min)
+                min = prices[i];
+        }
+
+        return result;
+    }
+};