Simple Permutations program in java


class permutations {

  static void print(int v[], int n) {
    for (int i = 0; i < n; i++) {
      System.out.print(v[i] + " ");
    }
    System.out.println("\n");
  }

  static void permute(int v[], int start, int n) {
    if (start == (n - 1)) {                           
//if its the end of the sequence genereated then print them
      print(v, n);
    }
    else {
      for (int i = start; i < n; i++) { 
//swap the start element woith the ith element to get n first sequeces
        int temp = v[start];
        v[start] = v[i];
        v[i] = temp;
        permute(v, start + 1, n);
 //of the n the first is kept constant the same is applied for the rest sequence
        v[i] = v[start];
        v[start] = temp;
      }
    }

  }

  public static void main(String[] args) {
    System.out.println("learn 2day permutaions!");
    int v[] = {
        1, 2, 3};
//this is the array which should contain the items to be permuted
    permute(v, 0, v.length);
  }
}

 

Simple Permutations program in java