生成包含范围内的唯一随机数数组 [英] Generate Array of Unique Random Numbers within Inclusive Range

问题描述

我正在尝试在 Apple Swift (iOS) 中编写一个函数，该函数将生成给定包含范围内的任意给定数量的唯一随机数，例如 0 到 10.因此，如果我说我想要 5 个唯一随机数在 0 到 10 之间，它将返回一个包含 [7, 10, 2, 3, 0] 或 [7, 10, 2, 8, 0] 等的数组.

I am trying to write a function in Apple Swift (iOS) that will generate any given amount of unique random numbers that are within a given inclusive range, say between 0 and 10. So if I say I want 5 unique random numbers between 0 and 10, it would return an array with [7, 10, 2, 3, 0] or [7, 10, 2, 8, 0], etc.

我有那部分工作:

// Returns an array of unique numbers
func uniqueRandoms(numberOfRandoms: Int, minNum: Int, maxNum: UInt32) -> [Int] {

    var uniqueNumbers = [Int]()

    while uniqueNumbers.count < numberOfRandoms {

        let randomNumber = Int(arc4random_uniform(maxNum + 1)) + minNum
        var found = false

        for var index = 0; index < uniqueNumbers.count; ++index {
                if uniqueNumbers[index] == randomNumber {
                    found = true
                    break
                }
        }

        if found == false {
            uniqueNumbers.append(randomNumber)
        }

    }

    return uniqueNumbers
}

print(uniqueRandoms(5, minNum: 0, maxNum: 10))

现在我想添加将我不想要的范围内的单个号码列入黑名单的功能.假设我仍然想要 0 到 10 之间的 5 个唯一随机数，但我不希望它包含 8 个.

Now I want to add the ability to blacklist a single number within that range that I don’t want. Say I still want 5 unique random numbers between 0 and 10 BUT I don’t want it to ever include 8.

那部分会导致无限循环(超过 25% 的时间或更多)，我不知道为什么?这是我所拥有的:

That part causes an endless loop (25%+ of the time or more) and I can’t figure out why? Here’s what I have:

var blackListNum = 8

// Returns an array of unique numbers
func uniqueRandoms(numberOfRandoms: Int, minNum: Int, maxNum: UInt32, checkBlackList: Bool = false) -> [Int] {

    var uniqueNumbers = [Int]()

    while uniqueNumbers.count < numberOfRandoms {

        let randomNumber = Int(arc4random_uniform(maxNum + 1)) + minNum
        var found = false

        for var index = 0; index < uniqueNumbers.count; ++index {
            if checkBlackList == false {
                if uniqueNumbers[index] == randomNumber {
                    found = true
                    break
                }
            } else {
                if uniqueNumbers[index] == randomNumber || uniqueNumbers[index] == blackListNum  {
                    found = true
                    break
                }
            }
        }

        if found == false {
            uniqueNumbers.append(randomNumber)
        }

    }

    return uniqueNumbers
}

print(uniqueRandoms(5, minNum: 0, maxNum: 10, checkBlackList: true))

我知道我的函数远非高效，因为我刚刚开始学习 Swift，但我想保持它的相似性，因为我想了解它是如何工作的.我不想简单地复制粘贴别人的更有效的解决方案而不理解它.我刚刚学习了变量、常量、if、while、for 等语句和其他基础知识，并希望保持不变.

I understand that my function is far from efficient because I am just starting to learn Swift but I want to keep it similar as I want to understand how it works. I don’t want to simply copy and paste someone else’s more efficient solution and not understand it. I have just learned variables, constants, if, while, for, etc. statements and the other basics and want to keep it to that.

推荐答案

您可以使用 Set 来存储所有随机数，直到达到预期的随机数，从而使您的生活更轻松:

You could make your live much easier using a Set to store all random numbers until you reach the expected number of randoms:

func uniqueRandoms(numberOfRandoms: Int, minNum: Int, maxNum: UInt32) -> [Int] {
    var uniqueNumbers = Set<Int>()
    while uniqueNumbers.count < numberOfRandoms {
        uniqueNumbers.insert(Int(arc4random_uniform(maxNum + 1)) + minNum)
    }
    return uniqueNumbers.shuffled()
}

print(uniqueRandoms(numberOfRandoms: 5, minNum: 0, maxNum: 10))

func uniqueRandoms(numberOfRandoms: Int, minNum: Int, maxNum: UInt32, blackList: Int?) -> [Int] {
    var uniqueNumbers = Set<Int>()
    while uniqueNumbers.count < numberOfRandoms {
        uniqueNumbers.insert(Int(arc4random_uniform(maxNum + 1)) + minNum)
    }
    if let blackList = blackList {
        if uniqueNumbers.contains(blackList) {
            while uniqueNumbers.count < numberOfRandoms+1 {
                uniqueNumbers.insert(Int(arc4random_uniform(maxNum + 1)) + minNum)
            }
            uniqueNumbers.remove(blackList)
        }
    }
    return uniqueNumbers.shuffled()
}

uniqueRandoms(numberOfRandoms: 3, minNum: 0, maxNum: 10, blackList: 8)  // [0, 10, 7]

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