// 设计一个函数，给出第一个数字、公差、元素个数，返回一个等差数列的数组
func generateArithmeticProgression(startValue: Int, commonDifference: Int, numberOfElements: Int) -> [Int] {
    var array = [Int](count: numberOfElements, repeatedValue: 0)
    for i in 0..<array.count {
        array[i] = startValue + commonDifference * i
    }
    return array
}
print(generateArithmeticProgression(5, commonDifference: 3, numberOfElements: 10))


// 给出一个数组判断是否为等差数列
func isProgression(array: [Int]) -> Bool {
    if array.count > 2 {
        let newArray = array.sort(<)
        let commonDiff = newArray[1] - newArray[0]
        for i in 1..<newArray.count - 1 {
            if newArray[i + 1] - newArray[i] != commonDiff {
                return false
            }
        }
    }
    return true
}
print(isProgression([1, 3, 4, 5, 6]))
print(isProgression([10, 8, 6, 4, 2]))
print(isProgression([300, 100, 200]))


// 设计一个函数给出一个长度，生成一个那么长度的由字母和数字组成的字符串验证码
extension String {
    // 对字符串进行扩展
    var length: UInt32 {
        get { return UInt32(self.characters.count) }
    }
    
    subscript(index: Int) -> Character {
        get { return self[self.startIndex.advancedBy(index)] }
    }
}

func randomInt(min: UInt32, _ max: UInt32) -> Int {
    return Int(arc4random_uniform(max - min + 1) + min)
}

func generateVerificationCode(length: Int) -> String {
    var code = ""
    if length > 0 {
        let str = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
        for _ in 0..<length {
            // code.append(str[randomInt(0, UInt32(str.characters.count) - 1)])
            code.append(str[randomInt(0, str.length - 1)])
            //code.append(str[str.startIndex.advancedBy(randomInt(0, UInt32(str.characters.count) - 1))])
        }
    }
    return code
}

for _ in 1...10 {
    print(generateVerificationCode(4))
}




// 设计一个学生找枪手考试的场景
// 代理模式
protocol ExamCandidate: class {
    func answerTheQuestion()
}

class LazyStudent: ExamCandidate {
    var name: String
    
    init(name: String) {
        self.name = name
    }
    
    func answerTheQuestion() {
    }
}

class Gunman: ExamCandidate {
    var name: String
    var target: LazyStudent?
    
    init(name: String) {
        self.name = name
    }
    
    func answerTheQuestion() {
        if let stu = target {
            print("姓名: \(stu.name)")
            print("奋笔疾书答案")
            print("提交试卷")
        }
    }
}

let stu = LazyStudent(name: "王大锤")
let gun = Gunman(name: "骆昊")
gun.target = stu
gun.answerTheQuestion()


// 委托回调模式
protocol ExamDelegate: class {
    
    func answerTheQuestion()
}

class LazyStudent {
    var name: String
    weak var delegate: ExamDelegate?
    
    init(name: String) {
        self.name = name
    }
    
    func joinExam() {
        print("姓名: \(name)")
        delegate?.answerTheQuestion()
    }
}

class Gunman: ExamDelegate {
    
    func answerTheQuestion() {
        print("奋笔疾书各种答案")
    }
}

let stu = LazyStudent(name: "王大锤")
let gun = Gunman()
stu.delegate = gun
stu.joinExam()




// 设计一个员工类和部门类，写上他们各自的属性和方法
enum Gender {
    case Male
    case Female
}

class Employee {
    var id: String
    var name: String
    var gender: Gender
    var tel: String?
    weak var dept: Department?
    
    init(id: String, name: String, gender: Gender) {
        self.id = id
        self.name = name
        self.gender = gender
    }
    
    func work() {
        print("工号为\(id)的\(name)正在工作.")
    }
    
    func haveRest() {
        print("\(name)正在休息.")
    }
}

class Department {
    var id: String
    var name: String
    var empsArray: [Employee] = []
    
    var numberOfEmps: Int {
        get { return empsArray.count }
    }
    
    init(id: String, name: String) {
        self.id = id
        self.name = name
    }
    
    func addEmp(emp: Employee) {
        empsArray.append(emp)
    }
    
    func removeEmp(id: String) -> Bool {
        if let index = empsArray.indexOf({ $0.id == id }) {
            empsArray.removeAtIndex(index)
            return true
        }
        return false
    }
}