java - java数组中不重复的随机数

Question

我进行了搜索，但找不到问题的答案。我必须创建一个乐透类型的模拟，6 个号码 + 奖金号码，没有重复。我已经设法让它工作，但在 6 数字数组中，位置 [1] 处的数字始终为 0。我确信它很简单，但我对此是全新的，因此我们将感激地接受任何帮助.下面的代码，我确信它到处都是......

import java.util.Arrays;

public class Lotto {

    public static void main(String[] args) {

        int[] Lotto=new int[6];
        final int MIN = 1;
        final int MAX = 45;

        for (int i = 0; i< Lotto.length; ++i)
        {

            Lotto [0] =MIN+ (int)(Math.random()*((MAX -MIN)+1));

            while (Lotto[1] == Lotto[0])
            {
                Lotto[1] =MIN+ (int)(Math.random()*((MAX -MIN)+1));
            }

            while ((Lotto[2] == Lotto[0]) || (Lotto[2] == Lotto[1]) )
            {
                Lotto[2] = MIN+ (int)(Math.random()*((MAX -MIN)+1));

            while ((Lotto[3] == Lotto[0]) || (Lotto[3] == Lotto[1]) || (Lotto[3] == Lotto[2]) )
            {
                Lotto[3] = MIN+ (int)(Math.random()*((MAX -MIN)+1));
            }

            while  ((Lotto[4] == Lotto[0]) || (Lotto[4] == Lotto[1]) || (Lotto[4] == Lotto[2]) ||   (Lotto[4] == Lotto[3]) )                        

            {
                Lotto[4] = MIN+ (int)(Math.random()*((MAX -MIN)+1));



                while  ((Lotto[5] == Lotto[0]) || (Lotto[5] == Lotto[1]) || (Lotto[5] == Lotto[2]) ||   (Lotto[5] == Lotto[3])||    (Lotto[5] == Lotto[4])) 

                {
                    Lotto[5] = MIN+ (int)(Math.random()*((MAX -MIN)+1));
                }


                int[] BonusNumber=new int[1];
                for (int j = 0; j< BonusNumber.length; ++j)
                {

                    BonusNumber [j] =1+ (int)(Math.random()*((45 -1)+1));
                }

                System.out.println("Winner  "  + Arrays.toString(Lotto));
                System.out.println("Bonus Number" +Arrays.toString(BonusNumber));   
            {


    }
            }
            }
        }
    }
}

Answer 1

更改此循环:

while (Lotto[1] == Lotto[0])
{
    Lotto[1] = random(MIN, MAX);
}

进入:

do {
    Lotto[1] = random(MIN, MAX);
} while (Lotto[1] == Lotto[0]);

其余的代码也相应地。你看出问题出在哪里了吗？

但是在开始重写相当复杂且难以维护的代码之前，请检查一下这个实现，它更容易理解并且......正确:

final int MIN = 1;
final int MAX = 45;

final List<Integer> allPossible = new ArrayList<Integer>(MAX - MIN + 1);
for (int i = MIN; i <= MAX; ++i) {
    allPossible.add(i);
}
Collections.shuffle(allPossible);
final List<Integer> lotto = allPossible.subList(0, 6);
int bonusNumber = allPossible.get(6);

System.out.println("Winner  "     + lotto);
System.out.println("Bonus Number" + bonusNumber);

Collections.shuffle()这里至关重要。