The document contains code to generate all permutations of a given list of integers. It takes in a list length from the user, generates the original list, then calls a recursive permute method to print out each permutation. The permute method swaps elements and recursively calls itself, backtracking with additional swaps to generate all permutations. It outputs the original list and all 24 permutations for a list of length 4 as an example.

1. Code:
import java.util.Random;
import java.util.Scanner;
class Test{
static void permute(int[] a, int k){
if (k == a.length){
for (int i = 0; i < a.length; i++){
System.out.print(a[i] + " ");
}
System.out.println();
}else{
for (int i = k; i < a.length; i++){
int temp = a[k];
a[k] = a[i];
a[i] = temp;
permute(a, k + 1);
temp = a[k];
a[k] = a[i];
a[i] = temp;
}
}
}
public static void main(String args[])
{
Random random = new Random();
Scanner sc = new Scanner(System.in);
System.out.print("Enter the length of list: ");
int N = sc.nextInt();
int[] sequence = new int[N];
for (int i = 1; i < N+1; i++)

2. sequence[i-1] = i;
System.out.println("The original sequence is: ");
for (int i = 0; i < N; i++)
System.out.print(sequence[i] + " ");
System.out.println(" The permuted sequences are as follows: ");
permute(sequence, 0);
sc.close();
}
}
Output:
Enter the length of list: 4
The original sequence is:
1 2 3 4
The permuted sequences are:
1 2 3 4
1 2 4 3
1 3 2 4
1 3 4 2
1 4 3 2
1 4 2 3
2 1 3 4
2 1 4 3
2 3 1 4
2 3 4 1
2 4 3 1
2 4 1 3
3 2 1 4
3 2 4 1
3 1 2 4
3 1 4 2
3 4 1 2
3 4 2 1
4 2 3 1

3. 4 2 1 3
4 3 2 1
4 3 1 2
4 1 3 2
4 1 2 3
Solution
Code:
import java.util.Random;
import java.util.Scanner;
class Test{
static void permute(int[] a, int k){
if (k == a.length){
for (int i = 0; i < a.length; i++){
System.out.print(a[i] + " ");
}
System.out.println();
}else{
for (int i = k; i < a.length; i++){
int temp = a[k];
a[k] = a[i];
a[i] = temp;
permute(a, k + 1);
temp = a[k];
a[k] = a[i];
a[i] = temp;
}
}
}
public static void main(String args[])
{

4. Random random = new Random();
Scanner sc = new Scanner(System.in);
System.out.print("Enter the length of list: ");
int N = sc.nextInt();
int[] sequence = new int[N];
for (int i = 1; i < N+1; i++)
sequence[i-1] = i;
System.out.println("The original sequence is: ");
for (int i = 0; i < N; i++)
System.out.print(sequence[i] + " ");
System.out.println(" The permuted sequences are as follows: ");
permute(sequence, 0);
sc.close();
}
}
Output:
Enter the length of list: 4
The original sequence is:
1 2 3 4
The permuted sequences are:
1 2 3 4
1 2 4 3
1 3 2 4
1 3 4 2
1 4 3 2
1 4 2 3
2 1 3 4
2 1 4 3
2 3 1 4
2 3 4 1
2 4 3 1
2 4 1 3

5. 3 2 1 4
3 2 4 1
3 1 2 4
3 1 4 2
3 4 1 2
3 4 2 1
4 2 3 1
4 2 1 3
4 3 2 1
4 3 1 2
4 1 3 2
4 1 2 3