How to store random number in a 2D arrays without repeating any number

Question

Program

Answer 1

If the chance of getting same number is big, and if there is a specified range for the numbers, I think one good way could be:
NUMBERS: numbers in array
MIN: minimum number
MAX: maximum number

Check whether NUMBERS > MAX - MIN.

Take a random number between MIN and MAX.

While the number is in the array, add 1 to the number.

When number > MAX, set it MIN.

When the number is not in the array, put it there and stop incrementing it by 1.

Answer 2

You would generate a random number, and if it is in the array, generate another one and see if it’s in the array.