Java Program to Implement the Alexander Bogomolny’s UnOrdered Permutation Algorithm for Elements From 1 to N

This is a java program to implement Alexander Bogomolny’s permutation algorithm. This version of program computes all possible permutations of numbers from 1 to N using Alexander Bogomolyn’s algorithm.

Here is the source code of the Java Program to Implement the Alexander Bogomolny’s UnOrdered Permutation Algorithm for Elements From 1 to N. The Java program is successfully compiled and run on a Windows system. The program output is also shown below.

package com.sanfoundry.combinatorial;
 
import java.util.Scanner;
 
public class AlexanderBogomolnyPermutation
{
    static int level = -1;
 
    public static void print(int[] value, int n)
    {
        if (value.length != 0)
        {
            for (int i = 0; i < value.length; i++)
            {
                System.out.print(value[i] + " ");
            }
            System.out.println();
        }
    }
 
    public static void visit(int[] Value, int N, int k)
    {
        level = level + 1;
        Value[k] = level;
        if (level == N)
            print(Value, N);
        else
            for (int i = 0; i < N; i++)
                if (Value[i] == 0)
                    visit(Value, N, i);
        level = level - 1;
        Value[k] = 0;
    }
 
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        System.out.println("Enter the size of the sequence:");
        int n = sc.nextInt();
        int sequence[] = new int[n];
        for (int i = 0; i < n; i++)
        {
            sequence[i] = 0;
        }
        System.out.println("The permutations are: ");
        visit(sequence, n, 0);
        sc.close();
    }
}

Output:

$ javac AlexanderBogomolnyPermutation.java
$ java AlexanderBogomolnyPermutation
 
Enter the size of the sequence:
4
The permutations are: 
1 2 3 4 
1 2 4 3 
1 3 2 4 
1 4 2 3 
1 3 4 2 
1 4 3 2 
2 1 3 4 
2 1 4 3 
3 1 2 4 
4 1 2 3 
3 1 4 2 
4 1 3 2 
2 3 1 4 
2 4 1 3 
3 2 1 4 
4 2 1 3 
3 4 1 2 
4 3 1 2 
2 3 4 1 
2 4 3 1 
3 2 4 1 
4 2 3 1 
3 4 2 1 
4 3 2 1