Permutaciones.java

public class Permutaciones {

    public static void permutacion(int array1[], int array2[]) {
        int size1 = array1 == null ? 0 : array1.length;
        int size2 = array2.length;

        if (size2 == 2) {
            /**
             * *********************** Caso Base ***********************
             */
            System.out.print("[");

            for (int i = 0; i < size1; i++)
                System.out.print(array1[i] + ",");
            System.out.println(array2[0] + "," + array2[1] + "]");
            System.out.print("[");

            for (int i = 0; i < size1; i++)
                System.out.print(array1[i] + ",");
            System.out.println(array2[1] + "," + array2[0] + "]");
        } else {
            /**
             * ******************** Caso Recursivo *********************
             */
            for (int i = 0; i < size2; i++) {
                int array1_temp[] = new int[size1 + 1];
                for (int j = 0; j < size1; j++)
                    array1_temp[j] = array1[j];

                array1_temp[size1] = array2[i];

                int counter = 0;
                int array2_temp[] = new int[size2 - 1];
                for (int j = 0; j < size2; j++) {
                    if (i == j)
                        continue;
                    array2_temp[counter++] = array2[j];
                }

                permutacion(array1_temp, array2_temp);
            }
        }
    }

    public static void permutacion(int array1[]) {
        int array2[] = null;
        permutacion(array2, array1);
    }

    public static void main(String[] args) {
        int size = 3;
        int array[] = new int[size];

        for (int i = 0; i < size; i++)
            array[i] = i + 1;

        permutacion(array);
    }

}