I found this interesting problem here:
https://javarevisited.blogspot.com/2014/11/how-to-find-missing-number-on-integer-array-java.html
but I think the solution is too long, see mine below:
import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
public class MissingIntegers {
public static void main(String[] args) {
Set<Integer> s1 = new HashSet<>(Arrays.asList(new Integer[]{1, 2, 3, 4, 9, 8}));
Set<Integer> s2 = new HashSet<>(IntStream.rangeClosed(1, 10).boxed().collect(Collectors.toList()));
s2.removeAll(s1);
System.out.println(s2);
}
}
In fact we don't need the intermediate List in the case of Set 2, we can use the toCollection method of Collectors:
Set<Integer> s2 = IntStream.rangeClosed(1, 10).boxed().collect(Collectors.toCollection(HashSet::new));
Next day I came up with another solution:
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
public class MissingIntegers {
public static void main(String[] args) {
List<Integer> L1 = Arrays.asList(new Integer[]{1, 2, 3, 4, 9, 2, 8});
List<Integer> L2 = IntStream.rangeClosed(1, 10).boxed().collect(Collectors.toCollection(ArrayList::new));
L2.removeAll(L1);
System.out.println(L2);
}
}
Settings.
![Mastering Multithreading with C++ [Video] Book Cover](https://d255esdrn735hr.cloudfront.net/sites/default/files/imagecache/ppv4_main_book_cover/bookretailers/V09707.png "Mastering Multithreading with C++ [Video] from Packt")
