#337 - Add Best Time to Buy and Sell Stock solution using java (#340)

Java/BestTimeToBuySellStock.java

@@ -0,0 +1,38 @@
+/**
+ * You are given an array prices where prices[i] is the price of a given stock on the ith day.
+ * You want to maximize your profit by choosing a single day to buy one stock and choosing a different day in the future to sell that stock.
+ * Return the maximum profit you can achieve from this transaction. If you cannot achieve any profit, return 0.
+ * 
+ * Example 1:
+ * Input: prices = [7,1,5,3,6,4]
+ * Output: 5
+ * Explanation: Buy on day 2 (price = 1) and sell on day 5 (price = 6), profit = 6-1 = 5.
+ * Note that buying on day 2 and selling on day 1 is not allowed because you must buy before you sell.
+ * 
+ * Example 2:
+ * Input: prices = [7,6,4,3,1]
+ * Output: 0
+ * Explanation: In this case, no transactions are done and the max profit = 0.
+ * 
+*/
+
+class Solution {
+    public int maxProfit(int[] prices) {
+        if (prices == null || prices.length == 0) {
+            return 0;
+        }
+
+        int minPrice = Integer.MAX_VALUE;
+        int maxProfit = 0;
+
+        for (int i = 0; i < prices.length; i++) {
+            if (prices[i] < minPrice) {
+                minPrice = prices[i];  // Update the minimum price
+            } else if (prices[i] - minPrice > maxProfit) {
+                maxProfit = prices[i] - minPrice;  // Calculate the new maximum profit
+            }
+        }
+
+        return maxProfit;
+    }
+}