CODEWITHSUNDEEP
javaarrays
mohamed hossam
mohamed hossam

Reputation: 15

fill two dimensional array with unique random number with java

Is there any way to fill two dimensional array with unique random number ? I tried so much but all of my tries are failed . I can do this

ArrayList<Integer> list = new ArrayList<>();
        
        for (int i = 1; i < 26; i++) {         //element will be in range (1,25)
            list.add(i);
        }
        Collections.shuffle(list);
        for (int j = 0; j < 5; j++) {
            System.out.print(list.get(j) + "     ");
        }
        System.out.println();

Upvotes: 1

Views: 516

Answers (4)

Ray Lee
Ray Lee

Reputation: 34

Does this can help ?

public static void main(String[] args)
   {
      // declare arrays
      int[][] ticketInfo;
      String[][] seatingChart;

      // create arrays
      ticketInfo = new int [2][3];
      seatingChart =  new String [3][2];

      // initialize the array elements
      ticketInfo[0][0] = 15;
      ticketInfo[0][1] = 10;
      ticketInfo[0][2] = 15;
      ticketInfo[1][0] = 25;
      ticketInfo[1][1] = 20;
      ticketInfo[1][2] = 25;
      seatingChart[0][0] = "Jamal";
      seatingChart[0][1] = "Maria";
      seatingChart[1][0] = "Jacob";
      seatingChart[1][1] = "Suzy";
      seatingChart[2][0] = "Emma";
      seatingChart[2][1] = "Luke";

      // print the contents
      System.out.println(ticketInfo);
      System.out.println(seatingChart);
   }

Upvotes: 0

user4910279
user4910279

Reputation:

Try this.

static List<List<Integer>> uniqueRandomNumbers(int height, int width) {
    List<Integer> list = IntStream.rangeClosed(1, height * width)
        .boxed()
        .collect(Collectors.toList());
    Collections.shuffle(list);
    List<List<Integer>> matrix = IntStream.range(0, height)
        .mapToObj(i -> list.subList(i * width, (i + 1) * width))
        .collect(Collectors.toList());
    return matrix;
}

and

List<List<Integer>> matrix = uniqueRandomNumbers(5, 5);
for (List<Integer> list : matrix)
    System.out.println(list);

result

[16, 4, 15, 14, 25]
[19, 11, 6, 21, 9]
[17, 20, 3, 1, 5]
[10, 7, 22, 18, 2]
[12, 13, 24, 23, 8]

Upvotes: 1

Unmitigated
Unmitigated

Reputation: 89224

If you wanted to print a 5x5 matrix of numbers from the List, you just need two layers of for loops. See the below code in action here.

ArrayList<Integer> list = new ArrayList<>();
for (int i = 1; i < 26; i++) { // element will be in range (1,25)
    list.add(i);
}
Collections.shuffle(list);
for (int j = 0; j < 5; j++) {
    for (int k = 0; k < 5; k++) {
        System.out.format("%3d     ", list.get(j * 5 + k));
    }
    System.out.println();
}
System.out.println();

Example Output:

  3       4      23      18      15     
  1       8      20       6       7     
  5      21      19       2      24     
 17      13      22      16      25     
 14       9      12      10      11

Upvotes: 1

GuanHao Yan
GuanHao Yan

Reputation: 29

I guess you can use combination of library which generates the random number and hashset. Hashset to remember the random number generated so far, and if duplicate is generated, you re-generate until it gives you the unseen number

Upvotes: 1

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