Swift 买卖股票的最佳时机 II

class Solution {
    func maxProfit(_ prices: [Int]) -> Int {

        if prices.count == 0  || prices.count == 1 {
            return 0
        }

        var sum = 0
        for i in 1..<prices.count {
            if prices[i] > prices[i - 1] {
                sum += prices[i] - prices[i - 1]
            }
        }
        return sum   
    }
}