# UVA 10038 – Jolly Jumpers

Easy problem. Take all differences, put them in a HashSet and then check if all the requred numbers are in the HashSet or not.

```import java.io.BufferedReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.HashSet;
import java.util.StringTokenizer;

/**
*
* @author Sanchit M. Bhatnagar
* @see http://uhunt.felix-halim.net/id/74004
*
*/
public class P10038 {
public static void main(String[] args) throws NumberFormatException, IOException {
PrintWriter out = new PrintWriter(System.out);
StringTokenizer st;

String line = null;
while ((line = br.readLine()) != null) {
st = new StringTokenizer(line.trim());
int N = Integer.parseInt(st.nextToken());
if (N == 1) {
out.println("Jolly");
} else {
HashSet<Integer> ans = new HashSet<Integer>();
int last = 0;
for (int i = 0; i < N; i++) {
if (i == 0) {
last = Integer.parseInt(st.nextToken());
} else {
int tmp = Integer.parseInt(st.nextToken());
last = tmp;
}
}

if (ans.size() != N - 1) {
out.println("Not jolly");
} else {
boolean found = true;
for (int i = 1; i < N; i++) {
if (!ans.contains(i)) {
found = false;
break;
}
}
if (found) {
out.println("Jolly");
} else {
out.println("Not jolly");
}
}
}
}
out.close();
br.close();
}
}
```

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