Given a list of bases for individual digit positions, find all possible numbers in that system

numberSystem.java

// Given digits,

public void calculateNumberSystem(int[] bases) {
  int[] num = new int[bases.length];
  
  HashSet<String> nums = new HashSet<String>();
  
  for(int i = bases.length-1; i >= 0; i--) {
    // Add result to set
    nums.add(Arrays.toString(num));
    
    if(num[i]+1 < bases[i]) {
      num[i] = num[i] + 1;
    } else {
      num[i] = 0;
    }
  }
}