hossamghareeb

class ViewController {
    var manager: Singleton {
        return Singleton.shared
    }
}

// in unit testing target
class TestingViewController: ViewController {
    override var manager: Singleton { Singleton() }
}

hossamghareeb

class Singleton {
    private static var instance = Singleton()
    #if DEBUG
    static var stubbedInstance: Singleton?
    #endif
    
    static var shared: Singleton {
        #if DEBUG
        if let stubbedInstance = stubbedInstance { return stubbedInstance }
        #endif

hossamghareeb

// Assuming you use one storyboard per view controller 

extension UIViewController {
    
    static func fromStoryboard() -> Self {
        let name = String(describing: Self.self)
        let sb = UIStoryboard(name: name, bundle: nil)
        return sb.instantiateViewController(identifier: name) as! Self
    }
}

hossamghareeb

Remove @main or @UIApplicationMain

hossamghareeb

// No memberwise initializer
struct Player {
    let name: String
    var score: Int = 0
    init(json: [String: AnyObject]) {

    }
}

// you have the both initializers:

hossamghareeb

struct Player {
    let name: String
    var score: Int = 0
}

let p1 = Player(name: "John")
let p2 = Player(name: "Sam", score: 100)

hossamghareeb

    override func viewDidLayoutSubviews() {
        super.viewDidLayoutSubviews()
        updateTableViewHeaderHeight()
    }
    
    private func updateTableViewHeaderHeight() {
        guard let headerView = tableView.tableHeaderView else { return }
        /// Get the size that should meet the constraints
        let size = headerView.systemLayoutSizeFitting(UIView.layoutFittingCompressedSize)
        guard size.height != headerView.frame.height else { return }

hossamghareeb

    private func swizzle(method: String, of class: String, to newMethod: String) {
        
        let original: Method
        let swizzled: Method
        guard let aClass = objc_getClass(`class`) as? AnyClass else { return }
        original = class_getInstanceMethod(aClass, Selector((method)))!
        swizzled = class_getInstanceMethod(aClass, Selector((newMethod)))!
        method_exchangeImplementations(original, swizzled)
    }
    

hossamghareeb

var arr = [1, 2, 5, 5, 6, 7, 10]
let pivot = arr.partition { $0 % 2 == 0 }
arr // [1, 7, 5, 5, 6, 2, 10]
let part1 = arr[..<pivot] // odd numbers
let part2 = arr[pivot...] // even numbers

hossamghareeb

/**
 Returns index of item if found. Otherwise returns -1 * position where the item should be insertd to
 */
func binarySearch(arr: [Int], start: Int, end: Int, k: Int) -> Int {
    var start = start
    var end = end
    var mid = 0
    while start <= end {
        mid = start + (end - start) / 2
        if arr[mid] == k {