/*
 * File: Perm.java
 * Purpose: Tests the permutation generation algorithm.
 * Compilation: javac Perm.java
 * Execution: java Perm
 * Author: San Skulrattanakulchai
 */

class Perm {
    private int n = 0;
    private int[] A;

    Perm(int k) {
        n = k;
        A = new int[n];
        for (int i = 0; i < n; i++)
            A[i] = i;
    }

    public void generate() {
        gen(0);
    }

    private void gen(int k) {
        if (k == n)
            System.out.println(java.util.Arrays.toString(A));
        else for (int i = k; i < n; i++) {
            int temp = A[i]; A[i] = A[k]; A[k] = temp;
            gen(k+1);
            temp = A[i]; A[i] = A[k]; A[k] = temp;
        }
    }

    public static void main(String[] args) {
        Perm p1 = new Perm(1);
        Perm p2 = new Perm(2);
        Perm p3 = new Perm(3);
        Perm p4 = new Perm(4);

        p1.generate();
        p2.generate();
        p3.generate();
        p4.generate();
    }
}