public class Quanpailie {
 public static void main(String[] args) {
  int[] a = new int[] {1,2,3};
  dfs(a, 0);
 }
public static void dfs(int[] a, int m) {
  int len = a.length;
  if(m == len) {
   for(int i : a) {
    System.out.print(i + " ");
   }
   System.out.println();
  }
  for(int i=m; i<len; i++) {
   swap(a, i, m);
   dfs(a, m+1);
   swap(a, i, m);
  }
 }
 public static void swap(int[] a, int i, int j) {
  int k = a[i];
  a[i] = a[j];
  a[j] = k;
 }
}