Class Solution
Easy
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.
Constraints:
1 <= prices.length <= 105
0 <= prices[i] <= 104
To solve the “Best Time to Buy and Sell Stock” problem in Java with a Solution
class, we’ll use a greedy algorithm. Below are the steps:
-
Create a
Solution
class: Define a class namedSolution
to encapsulate our solution methods. -
Create a
maxProfit
method: This method takes an arrayprices
as input and returns the maximum profit that can be achieved by buying and selling the stock. -
Initialize variables: Initialize two variables,
minPrice
to store the minimum price seen so far andmaxProfit
to store the maximum profit seen so far. InitializemaxProfit
to 0. -
Iterate through the prices array:
- For each price in the array:
- Update
minPrice
to the minimum of the current price andminPrice
. - Update
maxProfit
to the maximum of the current profit (price -minPrice
) andmaxProfit
.
- Update
- For each price in the array:
-
Return the maximum profit: After iterating through the entire array, return
maxProfit
.
Here’s the Java implementation:
class Solution {
public int maxProfit(int[] prices) {
if (prices == null || prices.length <= 1) return 0; // Check for empty array or single element
int minPrice = prices[0]; // Initialize minPrice to the first price
int maxProfit = 0; // Initialize maxProfit to 0
// Iterate through the prices array
for (int i = 1; i < prices.length; i++) {
minPrice = Math.min(minPrice, prices[i]); // Update minPrice
maxProfit = Math.max(maxProfit, prices[i] - minPrice); // Update maxProfit
}
return maxProfit; // Return the maximum profit
}
}
This implementation follows the steps outlined above and efficiently calculates the maximum profit that can be achieved by buying and selling the stock in Java.
-
Constructor Summary
-
Method Summary
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
-
Constructor Details
-
Solution
public Solution()
-
-
Method Details
-
maxProfit
public int maxProfit(int[] prices)
-