enumeratingGeneOrders.java

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

/******************************\
 * The solution is at the top *
 *                            *
 *   Created by : azhar556    *
\******************************/

public class A {
	static void nextPermutaion (int n, int[] arr) {
		for (int x : arr) {
			out.print(x + " ");
		}
		out.println();	
		while (true) {
			int por = n - 2;
			while (por >= 0 && arr[por] >= arr[por + 1]) {
				por--;
			}
			if (por < 0) {
				return;
			}
			for (int i = n - 1; i > por; i--) {
				if (arr[i] > arr[por]) {
					int swap = arr[por];
					arr[por] = arr[i];
					arr[i] = swap;
					break;
				}
			}
			for (int i = por + 1; i < (n + por + 1) / 2; i++) {
				int swap = arr[i];
				arr[i] = arr[n - 1 - (i - (por + 1))];
				arr[n - 1 - (i - (por + 1))] = swap;
			}
			for (int x : arr) {
				out.print(x + " ");
			}
			out.println();
		}
	}
	static int factorial (int n) {
		int res = 1;
		for (int i = 1; i <= n; i++) {
			res *= i;
		}
		return res;
	}
    static void solve() {
		int n = ni();
		int[] arr = new int[n];
		for (int i = 0; i < n; i++) {
			arr[i] = i + 1;
		}
		out.println(factorial(n));
		nextPermutaion(n, arr);
    }    

    public static void main(String[] args) {
        long time = System.currentTimeMillis();
        int t;// = ni();
        t = 1;
        while (t-- > 0) solve(); 
        err.println("Time elapsed : " + (System.currentTimeMillis() - time) / 1000F + " s.");
        err.close(); out.close();
    }

	static int[] radixSort(int[] f){ return radixSort(f, f.length); }
	static int[] radixSort(int[] f, int n)
	{
		int[] to = new int[n];
		{
			int[] b = new int[65537];
			for(int i = 0;i < n;i++)b[1+(f[i]&0xffff)]++;
			for(int i = 1;i <= 65536;i++)b[i]+=b[i-1];
			for(int i = 0;i < n;i++)to[b[f[i]&0xffff]++] = f[i];
			int[] d = f; f = to;to = d;
		}
		{
			int[] b = new int[65537];
			for(int i = 0;i < n;i++)b[1+(f[i]>>>16)]++;
			for(int i = 1;i <= 65536;i++)b[i]+=b[i-1];
			for(int i = 0;i < n;i++)to[b[f[i]>>>16]++] = f[i];
			int[] d = f; f = to;to = d;
		}
		return f;
	}

    static PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));
    static PrintWriter err = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.err)));
    static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    static StringTokenizer token;
        
    static String ns() {
        while (token == null || !token.hasMoreTokens()) {
            try {
                token = new StringTokenizer(br.readLine());
            }
            catch (IOException e) {
                throw new RuntimeException(e);
            }
        }
        return token.nextToken();
    }
    static char nc() {
        return Character.valueOf(ns().charAt(0));
    }
    static int ni() {
        return Integer.parseInt(ns());
    }
    static double nd() {
        return Double.parseDouble(ns());
    }
    static long nl() {
        return Long.parseLong(ns());
    }
}
// Collections Arrays Math
// Vector HashSet TreeSet HashMap TreeMap ArrayDeque