Merge pull request #33 from anurags10/main

Create BestTimeToSellAndBuyStock.java

DSA/BestTimeToSellAndBuyStockbyAnuragSingh.java

@@ -0,0 +1,66 @@
+/*
+Problem Statement: 
+Find the maximum profit that can be achieved from one transaction (buying and selling) in a given array of stock prices. 
+The i-th element of the array represents the price of a stock on day i.
+
+Approach:
+
+1. We will initialize two variables, "minPrice" and "maxProfit". 
+   - "minPrice" will store the minimum price seen so far, and it is initially set to the maximum possible integer value (`Integer.MAX_VALUE`).
+   - "maxProfit" will store the maximum profit, and it is initially set to 0.
+
+2. We will iterate through each price in the array:
+   - If the current price (arr[i]) is less than "minPrice", we will update "minPrice" to arr[i].
+   - If the current price minus "minPrice" (current profit) is greater than "maxProfit", we update "maxProfit" to this new profit.
+
+3. By the end of the iteration, "maxProfit" will hold the maximum possible profit from one transaction.
+
+Example:
+Input: [7, 1, 5, 3, 6, 4]
+After processing: minPrice = 1, maxProfit = 5 (buy on day 2 at price 1, sell on day 5 at price 6)
+
+Time Complexity: O(n), where n is the number of elements in the array.
+
+*/
+
+public class MaxProfit {
+
+    // Method to calculate the maximum profit from one transaction
+    public static int maxProfit(int[] prices) {
+        int minPrice = Integer.MAX_VALUE; // Initialize minPrice to the maximum integer value
+        int maxProfit = 0; // Initialize maxProfit to 0
+
+        // Loop through each price in the array
+        for (int price : prices) {
+            // If the current price is less than the minPrice, update minPrice
+            if (price < minPrice) {
+                minPrice = price;
+            }
+            // If selling at the current price yields a higher profit, update maxProfit
+            else if (price - minPrice > maxProfit) {
+                maxProfit = price - minPrice;
+            }
+        }
+
+        return maxProfit; // Return the maximum profit found
+    }
+
+    // Main method to run test cases
+    public static void main(String[] args) {
+        // Test cases
+        int[][] testCases = {
+            {7, 1, 5, 3, 6, 4},  // Test case 1
+            {7, 6, 4, 3, 1},      // Test case 2
+            {1, 2, 3, 4, 5},      // Test case 3
+            {3, 3, 3, 3, 3},      // Test case 4
+            {2, 1, 2, 1, 2}       // Test case 5
+        };
+        int[] expectedResults = {5, 0, 4, 0, 1}; // Expected results
+
+        // Running the test cases
+        for (int i = 0; i < testCases.length; i++) {
+            int result = maxProfit(testCases[i]);
+            System.out.println("Test case " + (i+1) + ": Expected " + expectedResults[i] + ", Got " + result + ", " + (result == expectedResults[i] ? "Pass" : "Fail"));
+        }
+    }
+}