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  1. char list[5] = {'1' , '2' , '3' , '4' , '5'};
  2.  
  3. main()
  4. {
  5.     int n;
  6.     scanf("%d", &n);
  7.  
  8.     if(n > 0 && n <= 5)
  9.         perm(n);
  10.  
  11.     return 0;
  12. }
  13.  
  14. typedef struct _PermInfo{
  15.     int i;
  16.     int j;
  17.     struct _PermInfo *parent;
  18. }PermInfo;
  19.  
  20. push(PermInfo **top, int i, int j)
  21. {
  22.     PermInfo *temp = (PermInfo *)malloc(sizeof(PermInfo));
  23.     temp->i = i;
  24.     temp->j = j;
  25.     temp->parent = *top;
  26.     *top = temp;
  27. }
  28.  
  29. pop(PermInfo **top)
  30. {
  31.     PermInfo *temp = (*top)->parent;
  32.     free(*top);
  33.     *top = temp;
  34. }
  35.  
  36. swap(char *a, char *b)
  37. {
  38.     char temp = *a;
  39.     *a = *b;
  40.     *b = temp;
  41. }
  42.  
  43. perm(int number)
  44. {
  45.     int i;
  46.     PermInfo *top = 0;
  47.  
  48.     push(&top, 0, 0);
  49.  
  50.     while(top)
  51.     {
  52.         if(top->i == number)
  53.         {
  54.             for(i = 0; i < number; ++i)
  55.                 printf("%c" , list[i]);
  56.             printf( "\n" );
  57.         }
  58.  
  59.         if(top->j < number)
  60.         {
  61.             swap(&list[top->i], &list[top->j]);
  62.             push(&top, top->i + 1, top->i + 1);
  63.         }
  64.         else
  65.         {
  66.             pop(&top);
  67.             if(top)
  68.             {
  69.                 swap(&list[top->i], &list[top->j]);
  70.                 ++top->j;
  71.             }
  72.         }
  73.     }
  74. }
  75.  
Success #stdin #stdout 0.01s 1720KB
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stdout 
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https://ideone.com/QDPcX1
language:
C (gcc 8.3)
created:
13 years ago
visibility:
secret

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