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).
 * The transaction fee is only charged once for each stock purchase and sale.
 * 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
 * 1 <= prices[i] < 5 * 104
 * 0 <= fee < 5 * 104
 */
impl Solution {
  pub fn max_profit(prices: Vec<i32>, fee: i32) -> i32 {
    let mut cash = 0i32;
    let mut hold = -prices[0];
    for &p in &prices[1..] {
      cash = cash.max(hold + p - fee);
      hold = hold.max(cash - p);
    }
    cash
  }
}