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HackerRank Exercise : Kangaroo Number Line Jumps Solved in Swift 5.0

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Given two kangaroos on a number line ready to jump in the positive direction, we have to figure out a way to get both kangaroos at the same location at the same time as part of the show. If it is possible, return YES , otherwise return NO . Read full problem statement from here Working solution in Swift           func kangaroo ( x1 : Int , v1 : Int , x2 : Int , v2 : Int ) -> String {         var multiplier = 1         // 1.         while (multiplier < 10000 ) {             // 2.             if (x1+(v1*multiplier) == x2+(v2*multiplier)) {                 return "YES"             }                          multiplier += 1         }            ...
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HackerRank Exercise: Subarray Division solved in Swift 5

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 In this post we can see complete solution for the HackerRank Exercise Subarray Division. The problem statement goes like this - Determine how many ways can divide the chocolate bar (as contiguous segment) between Lily and Ron given condition :  The length of the segment matches Ron's birth month The sum of the integers on the squares is equal to his birth day. Read complete challenge detail from HackerRank Working solution in Swift given below:      func birthday ( s : [ Int ] , d : Int , m : Int ) -> Int { var sCount = 0 var index = 0 // 1 while ( index < s. count ) { var dayLength = 0 let limit = index +m > s. count ? s. count : index +m // 2 for jIndex in index ..< limit { dayLength += s [ jIndex ] } // 3 if dayLength == d { sCount += 1 } ...
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HackerRank Exercise: Apple and Orange solved in Swift

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 In this post we can solve exercise problem "Apple and Orange" in which we should print the number of apples and oranges that land on Sam's house.  Read complete challenge detail from  hackerrank.com Full Swift Solution is given below: func countApplesAndOranges ( s : Int , t : Int , a : Int , b : Int , apples : [ Int ] , oranges : [ Int ]) -> Void { // 1 let applesDistance = apples. map ( { $ 0 + a }) var totalAppleOk = 0 applesDistance. forEach ({ ad in // 2 if ( s .. . t ) . contains ( ad ) { totalAppleOk = totalAppleOk + 1 } }) print ( " \( totalAppleOk ) " ) // prints number of Apples let orangeDistance = oranges. map ( { $ 0 + b }) var totalOrangeOk = 0 orangeDistance. forEach ({ od in if ( s .. . t ) . contains ( od ) { totalOrangeOk = totalOrangeOk ...
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Hackerrank Exercise : Utopian Tree solved in Swift

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In this post, we have Swift 5.0 solution for Hackerrank exercise - Utopian Tree . We have find out the height of  Utopian Tree, which goes through 2 cycles of growth every year. Each spring, it doubles in height. Each summer, its height increases by 1 meter. Full details of exercise link  hackerrank.com/challenges/utopian-tree/problem Here is the working solution:           func   utopianTree ( n :   Int )   ->   Int   {          var   height   =   0          for   cycle   in   0 .. . n   {              height   =   ( cycle   -   1 )   %   2   ==   0   ?   height   *   2   :   height   +   1            }  ...
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HackerRank Challenges : Migratory Birds solution in Swift

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In this post solution written in Swift for Migratory Bird Practice challenge from HackerRank. The problem statement goes like this - "Given an array of bird sightings where every element represents a bird type id, determine the id of the most frequently sighted type. If more than 1 type has been spotted that maximum amount, return the smallest of their ids"  For Example, Given array [1, 1, 2, 3, 3] There are two each of types 1 and 3, and one sighting of type 2. Pick the lower of the two types seen twice: type 1. Working solution in Swift 5.0:      func   migratoryBirds ( arr :   [ Int ])   ->   Int   {          // Write your code here          var   dict : [ String :   Int ]   =   [ : ]          // 1          arr . forEach ({  ...
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Implementing autocompletion OTP field in iOS

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Long waiting is over. !!  iOS 12 brings Autofill for OTP text field which is close to Android provided a decade back. Previously in iOS we used to toggle between OTP text screen and message inbox.  Which was hard to remember and time consuming resulting a bad user experience. Personally, I have been asked from the client/customer couple of times to implement autocompletion for OTP field and took me a lot of time to convey that it is not possible in iOS. Why Autofill was not possible previously?  We all know that Apple gives at most care for user privacy. When we see iOS architecture, each individual app is like a separate island. There is no inter-app bridge between apps (exception for Keychain and URLSchemes APIs which gives very limited scope). Thus we cannot read message content from inbox. Where to start Autofilling? First of all, the target SMS need to have the OTP Code with prefix string "Code" or "Passcode"on its message content. Beware of OTP c...
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Animating label text update - choosing a better way

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Recently I published a countdown app .  At one point of development - I have to show a timer on a UILabel which ticks on each seconds. As usual I started  setting text to a label object - self .timerLabel.text = someString Easy piece of cake right !?   But wait ... it won't take much user attention when timer ticks on every seconds. So I decided to make use of a simple animation while label gets text update. I found there are dozens of ways to animate a label. In this short article, I listed 3 best way you can animate text on a label. ( Spoiler Alert 👀- I decided to go with 3rd option)  1. Fade In - Fade out animation : CATransition class has got transition type `fade`. With timing function of CATransition - I was able to see the below result. let animation: CATransition = CATransition () animation.timingFunction = CAMediaTimingFunction (name: CAMediaTimingFunctionName .easeInEaseOut) animation.type = CATransitionType .fade animation.subtype = C...
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Cached Async Image in SwiftUI

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 SwiftUI’s AsyncImage is handy, but every time your view appears, it refetches the image—leading to flicker, delays, and unnecessary network use. What if you could fetch once, then reuse instantly? That's exactly what the Cached Async Image  delivers: a memory-powered caching layer that keeps SwiftUI image loading smooth, snappy, and resilient. First a simple in-memory cache without disk persistence. This will be thread-safe and auto-purges under memory pressure. A Singleton wrapping NSCache for URL → UIImage caching as follows : final class ImageCache {   static let shared = ImageCache()   private init() {}   private let cache = NSCache<NSURL, UIImage>()   func image(for url: URL) -> UIImage? {     cache.object(forKey: url as NSURL)   }   func insertImage(_ image: UIImage?, for url: URL) {     guard let image else { return }     cache.setObject(image, forKey: url as NSURL)   }   func clearAll() { ...
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Prevent Navigationbar or Tabbar overlapping Subview - solved for Card view

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Recently, I started with a Card view added as a subview of UIView in a view-controller. When a view controller created along subviews, it tends to use entire screen bounds and also slips behind Tab bar or Navigation bar. In my current situation, it's second case. Casually new iOS developers will write a patch by additional value for coordinate y and subtracting bar height from its size. A lot of them posted in SO threads too : How to prevent UINavigationBar from covering top of view? View got hidden below UINavigationBar iOS 7 Navigation Bar covers some part of view at Top So, how I got solved ? self.edgesForExtendedLayout = [] This  will avoid all subviews in a view controller get behind any bars. Read full apple  documentation on here. Full Source code below :  //Simple view controller where its view layed-out as a card. class WidgetCardViewController : UIViewController { var containerView = UIView () //MARK:- View Controller Life Cyc...
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UICollectionViewCell shows with wrong size on First time - Solved

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We commonly use Collection view where its cell size calculated run time. The flow layout delegate is responsible to return individual cell sizes. BUT in most of the cases, delegate method `collectionView: layout sizeForItem:` expects cell size too early. Before generating actual cell size. extension YourViewController : UICollectionViewDelegateFlowLayout { func collectionView ( _ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize { return CGSize (width: externalWidth, height: externalHeight) } } For instance, if a cell size depends on external view and its frame is not yet ready - results with wrong (or outdated) cell size. Typically happens for the first time view controller laid out all views. You can find similar queries in StackOverflow community : Collection view sizeForItemNotWorking UICollectionViewCell content wrong size on first load How to refresh UICollec...
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