Maximum profit by buying and selling a share at most twice in Swift by Peak Valley Approach.

Pick Valley Approach is for determining exacts highs and lows of a trend, with a trend being classified based on a specific movement in price.

Input:   price[] = {2, 30, 15, 10, 8, 25, 80}
Output:  100
Trader earns 100 as sum of 28 and 72
Buy at price 2, sell at 30, buy at 8 and sell at 80

Let start in Swift

class ViewController: UIViewController {

var price = [2, 30, 15, 10, 8, 25, 80]

var sum = 0

override func viewDidLoad() {

super.viewDidLoad()

for i in 1…price.count — 1 {

let checkDiffernce = price[i] — price[i — 1]

if (checkDiffernce > 0){

sum = sum + checkDiffernce

}

}

print(sum)

// Do any additional setup after loading the view.

}

}