You have 4 cards each containing a number from 1 to 9. You need to judge whether they could operated through *, /, +, -, (, )to get the value of 24. Example 1: Input: [4, 1, 8, 7] Output: True Expla

You‘re now a baseball game point recorder. Given a list of strings, each string can be one of the 4 following types: Integer (one round‘s score): Directly represents the number of points you get in th

In this problem, a tree is an undirected graph that is connected and has no cycles. The given input is a graph that started as a tree with N nodes (with distinct values 1, 2, ..., N), with one additio

In this problem, a rooted tree is a directed graph such that, there is exactly one node (the root) for which all other nodes are descendants of this node, plus every node has exactly one parent, excep

Given two strings A and B, find the minimum number of times A has to be repeated such that B is a substring of it. If no such solution, return -1. For example, with A = "abcd" and B = "cdabcdab". Retu

Given an array of integers nums and a positive integer k, find whether it‘s possible to divide this array into k non-empty subsets whose sums are all equal.  Example 1: Input: nums = [4, 3, 2, 3, 5, 2

On an infinite number line (x-axis), we drop given squares in the order they are given. The i-th square dropped (positions[i] = (left, side_length)) is a square with the left-most point being position

Given an array A of integers, we must modify the array in the following way: we choose an i and replace A[i] with -A[i], and we repeat this process K times in total.  (We may choose the same index i m

Design a HashMap without using any built-in hash table libraries. To be specific, your design should include these functions: put(key, value) : Insert a (key, value) pair into the HashMap. If the valu

  OC中的for循环写法：   for (int i = 0;i < 100;i++) { NSLog(@"i=%zd",i); }   Swift中的for循环写法：   let a = 100; for i in 0 ..< a { print("a=\(i)"); }   Swift中for循环不需要i的写法： let  a  =  100 ; for  _  in  0 ..

Given two integer arrays A and B, return the maximum length of an subarray that appears in both arrays. Example 1: Input: A: [1,2,3,2,1] B: [3,2,1,4,7] Output: 3 Explanation: The repeated subarr

我正试图在操场上用 SwiftKit和 Swift对游戏进行原型设计. 我无法让用户触摸回调工作. 这是我正在尝试的： let view:SKView = SKView(frame: CGRectMake(0, 0, 320, 586)) XCPShowView("Live view", view) class PrototypeScene: SKScene { override fu

This question询问是否可以在Swift中使用订阅CKRecord.虽然我已经知道如何做提问者想要的东西,但是它的每个排列都会给我一个堆栈溢出： subscript(key: String) -> CKRecordValue? { get { return objectForKey(key) as CKRecordValue? } set {

Given an array of integers nums, write a method that returns the "pivot" index of this array. We define the pivot index as the index where the sum of the numbers to the left of the index is equal to t

Given a C++ program, remove comments from it. The program source is an array where source[i] is the i-th line of the source code. This represents the result of splitting the original source code strin

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先上代码： xcode 9.4 import UIKit import WebKit class RootViewController: UIViewController, WKNavigationDelegate { var webView: WKWebView! override func viewDidLoad() { s

我没有调用任何UICollectionViewDelegateFlowLayout方法.有人可以帮我找到解决方案吗？ 在我的ViewDidLoad方法中,我为集合视图设置了委托和数据源 self.collectionView.delegate = self和 self.collectionView.dataSource = self 这是我的委托方法： func collectionView(co

我正在阅读 Swift编程语言手册,它提到了一个逃避关闭.关于转义闭包,我不知道它们的意思是“闭包作为参数传递给函数,但在函数返回后调用.”有人可以提供一个逃避闭包的例子吗？ 转义闭包的一个示例是某些异步任务中的完成处理程序,例如启动网络请求： func performRequest(parameters: [String: String], completionHandler: (NSData?

我正在尝试创建一个NSMutableDictionary来使用iOS中的密钥链,但是我收到以下错误. Could not find an overload for ‘init’ that accepts the supplied arguments 这是我正在使用的代码： var keychainQuery: NSMutableDictionary = NSMutableDictionary(ob

Given a list of daily temperatures T, return a list such that, for each day in the input, tells you how many days you would have to wait until a warmer temperature. If there is no future day for which

In a N x N grid representing a field of cherries, each cell is one of three possible integers. 0 means the cell is empty, so you can pass through; 1 means the cell contains a cherry, that you can pick

Given an array nums of integers, you can perform operations on the array. In each operation, you pick any nums[i] and delete it to earn nums[i] points. After, you must delete every element equal to nu

关键词： 类型与功能绑定、类型指定、访问控制。   类型约束的本质： 1、是否强制指定具有某些特征的类型；看类型构造器的定义本身是否对类型有约束； 2、访问控制：类型构造器的功能分为通用功能和约束功能； 通用功能任何实例类型都能访问； 约束功能，只有符合约束的构造实例能够访问。   类型与算法（功能）绑定；对引用类型施加约束，实质上是对构造类型开放了一批底层的功能接口； 类型构造器可以在这些功能接

我想使用通用协议类型作为函数返回类型,如下所示： protocol P { associatedtype T func get() -> T? func set(v: T) } class C<T>: P { private var v: T? func get() -> T? { return v } func set(v: T) { self.v

我希望能够在用户向下滑动时更改节点的physicsBody高度,但除了重置整个physicsBody之外,还无法找到如何执行此操作. 当我最初加载节点时,我使用以下代码： nodeHero.color = UIColor .grayColor() nodeHero.size.width = 20 nodeHero.size.height = 45 nodeHero.posi

我正在尝试翻译SKScene * scene = [GameScene sceneWithSize：skView.bounds.size];快速但我得到了错误 ‘sceneWithSize’ is unavailable: use object construction ‘SKScene(size:)’. 我正在使用viewWillLayoutSubviews并删除viewDidLoad(),因为

You have a lock in front of you with 4 circular wheels. Each wheel has 10 slots: ‘0‘, ‘1‘, ‘2‘, ‘3‘, ‘4‘, ‘5‘, ‘6‘, ‘7‘, ‘8‘, ‘9‘. The wheels can rotate freely and wrap around: for example we can turn

  import UIKit //UIPickerView 的委托协议是 UIPickerViewDelegate，数据源是 UIPickerViewDataSource。我们需要在视图控制器中声明实现 UIPiekerViewDelegate 和 UIPickerViewDataSource 协议。 class RootViewController: UIViewController,

我知道如何在新的快速项目中使用 cocoapods吗？ 但是如何使用 swift创建自己的cocoapod呢？ pod lib lint产生此错误： - NOTE | [xcodebuild] warning: no rule to process file '/Pod/Classes/SomeClass.swift' of type text for architecture armv7 编