import Foundation

extension Array where Element: Comparable {
    
    func quicksorted(by areInIncreasingOrder: (Element, Element) throws -> Bool = (<)) rethrows -> Array {
        
        guard let pivot = self.first else {
            return self
        }
        
        let rest = self.dropFirst()

        return try rest.filter { try areInIncreasingOrder($0, pivot) }.quicksorted(by: areInIncreasingOrder)
            + [pivot]
            + rest.filter { try !areInIncreasingOrder($0, pivot) }.quicksorted(by: areInIncreasingOrder)
    }
    
}


let arr = [5,2,5,7,4,8,0,6,4,1,2,3,3,6,3]

print(arr.quicksorted())