1 public class A { 2     static int k=0; 3     static int temp_k=0; 4     static int p=0; 5     static int q=0; 6     public static void main(String args[]) { 7         char[] ss = { ‘1‘, ‘2‘, ‘3‘,‘4‘,‘5‘,‘1‘, ‘2‘, ‘3‘,‘4‘,‘5‘}; 8         permutation(ss, 0); 9         if(temp_k == k)  {10             System.out.println(k);11             System.out.println(p);12             System.out.println(q);13         }14     }15     public static void permutation(char[] ss, int i) {16         17         if (ss == null || i < 0 || i > ss.length) {18             return;19         }20         if (i == ss.length) {21             String a = new String(ss);    22             k++;23             temp_k = k;24             if(k==3628800)25             System.out.println(a);26         } else {27             for (int j = i; j < ss.length; j++) {28                 char temp = ss[j];// 交换前缀,使之产生下一个前缀29                 ss[j] = ss[i];30                 ss[i] = temp;31                 p++;32                 permutation(ss, i + 1);33                 q++;34                 temp = ss[j]; // 将前缀换回来,继续做上一个的前缀排列.35                 ss[j] = ss[i];36                 ss[i] = temp;37             }38         }39     }40 }

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