在二维数组的列中查找重复数字

Question

I'm making a digital Bingo board using numbers and I want all the numbers to be unique. So I'm trying to create an algorithm that will loop through the column, find repeating numbers and then replace them with a random number between two certain numbers.

This is what I have so far:

public void bingoBoardGenrerator(int[][] bingoBoard) {
    for (int row = 0; row < bingoBoard.length; row++) {
        int random = (int) (Math.random() * 15) + 1;
        bingoBoard[row][0] = random;
        for (int j = 1; j < bingoBoard.length; j++) {
            if (bingoBoard[j][0] == random) {
                bingoBoard[row][0] = (int) (Math.random() * 15) + 1;
            }
        }

The output should look like this but without the repeating numbers in the columns:

 Free space = 0

B   I   N   G   O   

5   25  36  53  61  
9   19  36  60  62  
1   17  0   54  63  
6   20  37  57  71  
5   19  39  57  69  

Any help would be really appreciated!

Answer 1

For the "B" column:

1. Create an ArrayList with the Integers 1-15.
2. Then use the Collections.sort() to randomize the numbers.
3. Then take the first 5 numbers from the ArrayList and add them to your Array

Repeat the above steps for the I, N, G, O columns each using the appropriate range of numbers.

Or another approach (for the B) is to:

1. Create a Set.
2. Generate a random number in the range 1-15
3. Add the number to the set
4. If the set contain 5 number you are finished. If not, repeat steps 2 - 4.

Repeat the above steps for the other columns.