romyilano

// brushing up on url components
// 

class CryptoApi {
    static let host = "min-api.cryptocompare.com"
    static let allCoinsPath = "/data/all/coinlist"
    var allCoinsUrl: URL? = {
        var urlComponents = URLComponents()
        urlComponents.scheme = "https"
        urlComponents.host = CryptoApi.host

romyilano

// https://stackoverflow.com/questions/23806751/strong-reference-to-a-weak-references-inside-blocks
__weak typeof(self) weakSelf = self;
void (^someBlock)(id) = ^(id data){
    if (weakSelf != nil) {
       // last remaining strong reference released by another thread. 
       // weakSelf is now set to nil.
       [myArray addObject:weakSelf];
    }
});

romyilano

// https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/ProgrammingWithObjectiveC/WorkingwithBlocks/WorkingwithBlocks.html#//apple_ref/doc/uid/TP40011210-CH8-SW16

@interface XYZBlockKeeper : NSObject
@property (copy) void (^block)(void);
@end

@implementation XYZBlockKeeper
- (void)configureBlock {
    self.block = ^{
        [self doSomething];    // capturing a strong reference to self

romyilano

protocol RowPresentable {
    var string: String { get }
    // it conforms to both protocol + class
    var rowVC: UIViewController & PanModalPresentable { get }
}

romyilano

// thanks dude
// https://medium.com/@dushyant_db/setting-up-a-container-view-using-interface-builder-and-via-code-7ac1a7f0a0d6 

override func viewDidLoad() {
    super.viewDidLoad()
    
    guard let childVC = self.storyboard?.instantiateViewController(withIdentifier: "ChildViewController") as? ChildViewController else {
      return
    }
addChildViewController(childVC)

romyilano

// thanks dude
// https://medium.com/@dushyant_db/setting-up-a-container-view-using-interface-builder-and-via-code-7ac1a7f0a0d6 

override func viewDidLoad() {
    super.viewDidLoad()
    
    guard let childVC = self.storyboard?.instantiateViewController(withIdentifier: "ChildViewController") as? ChildViewController else {
      return
    }
addChildViewController(childVC)

romyilano

public class ListNode {
    public var val: Int
    public var next: ListNode?
    public init(_ val: Int) {
        self.val = val
        self.next = nil
    }
    
    convenience init?(withArray array: [Int]) {
        guard let firstVal = array.first else { return nil }

romyilano

// https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/MemoryMgmt/Articles/mmAutoreleasePools.html

– (id)findMatchingObject:(id)anObject {
 
    id match;
    while (match == nil) {
        @autoreleasepool {
 
            /* Do a search that creates a lot of temporary objects. */
            match = [self expensiveSearchForObject:anObject];

romyilano

func hasCycle(head: ListNode) -> Bool {
    while let hareNext = hare.next?.next, let tortoiseNext = tortoise.next {
        hare = hareNext
        tortoise = tortoiseNext
        if hare.val == tortoise.val {
            return true
        }
    }
    return false
}

romyilano

// assuming nodes have no duplicate values
var head = ListNode(5)
head.next = ListNode(7)
let secondNode = head.next
head.next?.next = ListNode(8)
head.next?.next?.next = ListNode(12)
head.next?.next?.next?.next = secondNode

var tortoise = head
var hare = head