Merge pull request #327 from Stackingrule/dev

feat:add Solution.cpp for 0121. Best Time to Buy and Sell Stock

Author: Stackingrule

solution/0100-0199/0121.Best Time to Buy and Sell Stock/Solution.cpp

@@ -0,0 +1,17 @@
+class Solution {
+public:
+    int maxProfit(vector<int>& prices) {
+        const int n = prices.size();
+        if (n < 1) return 0;
+        vector<int> min_prices(n);
+        vector<int> max_profit(n);
+        min_prices[0] = prices[0];
+        max_profit[0] = 0;
+        for (int i = 1; i < n; ++i) {
+            min_prices[i] = min(min_prices[i - 1], prices[i]);
+            max_profit[i] = max(max_profit[i - 1], prices[i] - min_prices[i - 1]);
+        }
+
+        return max_profit[n - 1];
+    }
+};