solve.swift

class Solution {
    func finalPrices(_ prices: [Int]) -> [Int] {
        var answer = [Int]()
    
        for (index, price) in prices.enumerated() {
            if index+1 == prices.count {
                answer.append(price)
            } else {
                if price >= prices[index+1] {
                    let discount = prices[index+1]
                    answer.append(price - discount)
                } else {
                    for afterIndex in index+2..<prices.count {
                        if price >= prices[afterIndex] {
                            let discount = prices[afterIndex]
                            answer.append(price - discount)
                            break
                        }
                    }
                    if index == answer.count {
                        answer.append(price)
                    }
                }
            }
        }

        return answer
    }
}