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import Foundation

final class Solution {
    // Using a Set for result storage prevents unintended duplicates from being added.
    private var result: Set<[Character]> = Set()

    func generateParans(_ num: Int) {
        // Build the seed array for sending into Heap's Algorithm gen function.
        // We create an array of `num` opening parans and combine it with an
        // array of `num` closing parans.

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// It's possible that the text is truncated not because of the line break mode,
// but because the text is outside the drawable bounds
if isTruncating == false {
  // This gives us the range of all the characters that have been already laid out
  // into the text container by the layout manager. 
  let glyphRange = layoutManager.glyphRange(for: textContainer)
  
  // This provides the range of glyphs (not characters) that have been generated for the text container.
  // Since a glyph is a graphical representation of a character, and more than one glyph can be used 
  // to represent a single character, this should always be equal or greater than the number of

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var isTruncating = false
// Make a range that encompases the entire text length.
let maxRange = NSRange(location: 0, length: Int.max)
// Use the layout manager to go through all of its line fragments within the range (entire text because of max range).
// More in-depth information is available within the NSLayoutManager docs.
layoutManager.enumerateLineFragments(forGlyphRange: maxRange) { _, _, _, glyphRange, stop in
  // Ask the layout manager to find the range of the truncation glyph (...) within this line fragment
  let truncatedRange = self.layoutManager.truncatedGlyphRange(inLineFragmentForGlyphAt: glyphRange.lowerBound)
  // If the truncatedRange has a valid location that means the layout manager has detected the truncation glyph.
  if truncatedRange.location != NSNotFound {

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extension UITextView {
  // Massive credit to Dave Delong for his extensive help with this solution.
  /// Returns whether or not the `UITextView` is displaying truncated text. This includes text
  /// that is visually truncated with an ellipsis (...), and text that is simply cut off through
  /// word wrapping.
  ///
  /// - Important:
  /// This only works properly when the `NSLineBreakMode` is set to `.byTruncatingTail` or `.byWordWrapping`.
  ///
  /// - Remark:

alexpersian

import Foundation

final class DepthFirstSearch<T: Hashable> {

    private let graph: Graph<T>
    private var searchStack: [T] = []
    private var visited: Set<T> = Set()

    init(graph: Graph<T>) {
        self.graph = graph

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// Update is called once per frame
public override func update(_ currentTime: TimeInterval) {
  // Collect a reference frame for the node's current position
  let currentFrame = dvdNode.calculateAccumulatedFrame()

  // Top bound
  if currentFrame.maxY >= self.frame.maxY {
    moveTransform.ty = -1.0
    dvdNode.run(changeColor)
  }

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// ...

private var changeColor: SKAction {
  return SKAction.colorize(with: UIColor.generateRandomColor(), colorBlendFactor: 1.0, duration: 0)
}

// ...

private func setup() {
  addChild(dvdNode)

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extension UIColor {
  static func generateRandomColor() -> UIColor {
    let hue = CGFloat(arc4random() % 256) / 256 // use 256 to get full range from 0.0 to 1.0
    return UIColor(hue: hue, saturation: 1, brightness: 1, alpha: 1) // Max saturation, max brightness
  }
}

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import SpriteKit

public class DVDScene: SKScene {

  private let dvdNode: SKNode

  public init(node: SKNode, size: CGSize) {
    self.dvdNode = node
    super.init(size: size)
    setup()

alexpersian

import SpriteKit
import PlaygroundSupport

let viewFrame = CGRect(x: 0, y: 0, width: 400, height: 400)
let view = SKView(frame: viewFrame)

let dvdNode = SKSpriteNode(imageNamed: "dvd-logo.png")
dvdNode.size = CGSize(width: 100, height: 47)

let mainScene = SKScene(size: view.frame.size)