Answer by user2023861 for Check if all lotto numbers are covered in input

Your first loop could be simplified:

while (ticketNumber != 0) {    neededNumbers[ticketNumber - 1] = true;    ticketNumber = input.nextInt();}

Arrays allow random access, so if you can map your input (a one-based ticketNumber integer) to your array indexing (zero-based), you can avoid looping through the array. I suspect you had linked-lists on your mind when developing your algorithm.