Question

我必须创建15个问题，其中只有10个将随机显示。（15个数组超过15个数组）。我需要确保在随机过程中没有重复的数组。

public static void main(String() args){
   String question_1 = question_One();
   //to question 15
   String question_15 = question_fifteen();
   String [] question = new String [14]; 
   question[0] = question_1;
   question[1] = question_2;
   //to question 15
   question[14] = question_15;
   int random = (int) (Math.random()*11);
       System.out.print(question[random]);
}

Answer 1

我会采取一系列问题，将其改组，然后从形成前十个问题开始。但是，Java中的数组非常有限，使用适当的Collection，例如ArrayList：

，这样做会容易得多。

// Build the question list:
List<String> questions = new ArrayList<>(15);
questions.add(question_1);
questions.add(question_2);
// etc...

// Shuffle it:
Collections.shuffle(questions);

// Ask the first ten:
List<String> questionsToAsk = questions.subList(0, 10);

编辑：
使用ArrayList和Collections只是一种便利。同样的逻辑也应该与数组一致，尽管它需要你自己实现一些：

// Build the question list:
String[] questions = new String[15];
questions[0] = question_1;
questions[1] = question_2;
// etc...

// Shuffle the first 10 elements.
// Although the elements can be taken from indexes above 10,
// there no need to continue shuffling these indexes.
Random r = new Random();
for (int i = 0; i < 10; ++i) {
    int swapIndex = r.nextInt(15 - i) + i;
    String temp = questions[i];
    questions[i] = questions[swapIndex];
    questions[swapIndex] = temp;

// Ask the first ten:
String[] questionsToAsk = new String[10];
for (int i = 0; i < 10; ++i) {
    questionsToAsk[i] = questions[i];
}

随机数组没有重复

1 个答案: