Codeforces Round #223 (Div. 2) B Sereja and Stairs

// Codeforces Round #223 (Div. 2) B Sereja and Stairs
// Problem: http://codeforces.com/contest/381/problem/B

import java.io.*;
import java.math.*;
import java.util.*;

//Codeforces
public class MainCodeforces1 {
private static MyScanner in;
private static PrintStream out;
private static boolean LOCAL_TEST = false;

private static void solve() throws IOException
{
int n = in.nextInt();
Integer[] x = new Integer[n];
for (int i = 0; i < x.length; i++) {
x[i] = in.nextInt();
}
Arrays.sort(x, Collections.reverseOrder());
ArrayList<Integer> list2 = new ArrayList<Integer>();
HashSet<Integer> set1 = new HashSet<Integer>();
list2.add(x[0]);
for (int i = 1; i < x.length; i++) {
if (x[i] < x[i - 1]) {
list2.add(x[i]);
}
else {
if (!x[i].equals(x[0])) {
set1.add(x[i]);
}
}
}
ArrayList<Integer> list1 = new ArrayList<Integer>();
list1.addAll(set1);
Collections.sort(list1);
list1.addAll(list2);
out.println(list1.size());
for (int i = 0; i < list1.size(); i++) {
if (i > 0)
out.print(" ");
out.print(list1.get(i));
}
out.println();
}

public static void main(String[] args) throws IOException {
// helpers for input/output
out = System.out;
try {
String cname = System.getenv("COMPUTERNAME");
if (!cname.equals(""))
LOCAL_TEST = true;
} catch (Exception e) {
}
if (LOCAL_TEST) {
in = new MyScanner("E:\\zin.txt");
}
else {
boolean usingFileForIO = false;
if (usingFileForIO) {
// using input.txt and output.txt as I/O
in = new MyScanner("input.txt");
out = new PrintStream("output.txt");
}
else {
in = new MyScanner();
out = System.out;
}
}

solve();
}

// =====================================
static class MyScanner {
BufferedReader bufReader;
StringTokenizer strTok;

public MyScanner() throws IOException
{
bufReader = new BufferedReader(new InputStreamReader(System.in));
strTok = new StringTokenizer("");
}

public MyScanner(String inputFile) throws IOException {
bufReader = new BufferedReader(new InputStreamReader(new FileInputStream(
inputFile)));
strTok = new StringTokenizer("");
}

String GetNextToken() throws IOException {
if (!strTok.hasMoreTokens())
strTok = new StringTokenizer(bufReader.readLine());
return strTok.nextToken();
}

public int nextInt() throws IOException {
return Integer.valueOf(GetNextToken());
}

public long nextLong() throws IOException {
return Long.valueOf(GetNextToken());
}

public double nextDouble() throws IOException {
return Double.valueOf(GetNextToken());
}

public String nextString() throws IOException {
return GetNextToken();
}

public String nextLine() throws IOException {
return bufReader.readLine();
}

public int countTokens() {
return strTok.countTokens();
}

public boolean hasMoreTokens() {
return strTok.hasMoreTokens();
}
}

}