feat: Add StockProfitCalculator new algorithm with Junit tests

Author: Hardvan

src/main/java/com/thealgorithms/greedyalgorithms/StockProfitCalculator.java

@@ -0,0 +1,32 @@
+package com.thealgorithms.greedyalgorithms;
+
+/**
+ * The StockProfitCalculator class provides a method to calculate the maximum profit
+ * that can be made from a single buy and sell of one share of stock.
+ * The approach uses a greedy algorithm to efficiently determine the maximum profit.
+ *
+ * @author Hardvan
+ */
+public class StockProfitCalculator {
+
+    /**
+     * Calculates the maximum profit from a list of stock prices.
+     *
+     * @param prices an array of integers representing the stock prices on different days
+     * @return the maximum profit that can be achieved from a single buy and sell
+     * transaction, or 0 if no profit can be made
+     */
+    public static int maxProfit(int[] prices) {
+        if (prices == null || prices.length == 0) {
+            return 0;
+        }
+
+        int minPrice = prices[0];
+        int maxProfit = 0;
+        for (int price : prices) {
+            minPrice = Math.min(price, minPrice);
+            maxProfit = Math.max(price - minPrice, maxProfit);
+        }
+        return maxProfit;
+    }
+}

src/test/java/com/thealgorithms/greedyalgorithms/StockProfitCalculatorTest.java

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+package com.thealgorithms.greedyalgorithms;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class StockProfitCalculatorTest {
+
+    @ParameterizedTest
+    @MethodSource("provideTestCases")
+    public void testMaxProfit(int[] prices, int expected) {
+        assertEquals(expected, StockProfitCalculator.maxProfit(prices));
+    }
+
+    private static Stream<Arguments> provideTestCases() {
+        return Stream.of(Arguments.of(new int[] {7, 1, 5, 3, 6, 4}, 5), Arguments.of(new int[] {7, 6, 4, 3, 1}, 0), Arguments.of(new int[] {5, 5, 5, 5, 5}, 0), Arguments.of(new int[] {10}, 0), Arguments.of(new int[] {1, 5}, 4), Arguments.of(new int[] {2, 4, 1, 3, 7, 5}, 6));
+    }
+}