Best Time to Buy and Sell Stock with Transaction Fee

You are given an array prices where prices[i] is the price of a given stock on the ith day, and an integer fee representing a transaction fee.

Find the maximum profit you can achieve. You may complete as many transactions as you like, but you need to pay the transaction fee for each transaction.

Note: You may not engage in multiple transactions simultaneously (i.e., you must sell the stock before you buy again).

Example 1:

Input: prices = [1,3,2,8,4,9], fee = 2
Output: 8
Explanation: The maximum profit can be achieved by:
- Buying at prices[0] = 1
- Selling at prices[3] = 8
- Buying at prices[4] = 4
- Selling at prices[5] = 9
The total profit is ((8 - 1) - 2) + ((9 - 4) - 2) = 8.

Example 2:

Input: prices = [1,3,7,5,10,3], fee = 3
Output: 6

Constraints:

• 1 < prices.length <= 5 * 104

• 0 < prices[i], fee < 5 * 104

Solution:

class Solution {
    public int maxProfit(int[] prices, int fee) {
        if(prices.length==0 || prices.length<=1) return 0;
        int havingStock=-prices[0];
        int notHavingStock = 0;
        
        for(int i=1;i<prices.length;i++)
        {
            havingStock = Math.max(havingStock,notHavingStock-prices[i]);
            notHavingStock = Math.max(notHavingStock,havingStock+prices[i]-fee);
        }
        return notHavingStock;
    }
}