714. Best Time to Buy and Sell Stock with Transaction Fee

Your are given an array of integers `prices`, for which the `i`-th element is the price of a given stock on day `i`; and a non-negative integer `fee` representing a transaction fee.

You may complete as many transactions as you like, but you need to pay the transaction fee for each transaction. You may not buy more than 1 share of a stock at a time (ie. you must sell the stock share before you buy again.)

Return the maximum profit you can make.

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] = 1Selling at prices[3] = 8Buying at prices[4] = 4Selling at prices[5] = 9The total profit is ((8 - 1) - 2) + ((9 - 4) - 2) = 8.
```

Note:

• `0 < prices.length <= 50000`.
• `0 < prices[i] < 50000`.
• `0 <= fee < 50000`.
• 714. Best Time to Buy and Sell Stock with Transaction Fee
``````struct Solution;

impl Solution {
fn max_profit(prices: Vec<i32>, fee: i32) -> i32 {
let n = prices.len();
let mut cash = 0;
let mut hold = -prices[0];
for i in 1..n {
cash = cash.max(hold + prices[i] - fee);
hold = hold.max(cash - prices[i]);
}
cash
}
}

#[test]
fn test() {
let prices = vec![1, 3, 2, 8, 4, 9];
let fee = 2;
let res = 8;
assert_eq!(Solution::max_profit(prices, fee), res);
}
``````