import java.util.HashSet;
public class MyClass {
public static void printMissingElements(int arr[], int range_start, int range_end) {
HashSet<Integer> hset = new HashSet<>();
for (int i = 0; i < arr.length; i++) {
hset.add(arr[i]);
}
for (int i = range_start; i <= range_end; i++) {
if (!hset.contains(i)) {
System.out.print(i + " ");
}
}
}
public static void main(String args[]) {
int arr[] = {2, 4, 5, 7, 9};
int range_start = 1, range_end = 9;
printMissingElements(arr, range_start, range_end);
}
}
/*
run:
1 3 6 8
*/