best time to buy and sell stock solution

Author: Jeongwon Na

best-time-to-buy-and-sell-stock/njngwn.java

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+// Time Complexity: O(n), n: prices.length
+// Space Complexity: O(1), because 3 int-variables are declared -> O(1)+O(1)+O(1)
+class Solution {
+    public int maxProfit(int[] prices) {
+        int buyPrice = prices[0];
+        int sellPrice = 0;
+        int profit = 0;  // store maxProfit
+
+        for (int i = 1; i < prices.length; ++i) {
+            buyPrice = Math.min(buyPrice, prices[i]);
+            profit = Math.max(profit, prices[i] - buyPrice);
+        }
+
+        return profit;
+    }
+}