hdu1016(dfs)

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      #include
    
      "
    
      iostream
    
      "
    
      

    
      using
    
       
    
      namespace
    
       std;

    
      int
    
       a[
    
      1001
    
      ],b[
    
      1001
    
      ];

    
      int
    
       used[
    
      1001
    
      ];

    
      int
    
       n;

    
      int
    
       i,j,q,t;


    
      void
    
       Init()
{
 
    
      for
    
      (i
    
      =
    
      1
    
      ;i
    
      <
    
      40
    
      ;i
    
      ++
    
      ) b[i]
    
      =
    
      1
    
      ;
 
    
      for
    
      (i
    
      =
    
      2
    
      ;i
    
      <
    
      40
    
      ;i
    
      ++
    
      )
 {
 
    
      for
    
      (j
    
      =
    
      2
    
      ;j
    
      <
    
      40
    
      ;j
    
      ++
    
      )
 b[i
    
      *
    
      j]
    
      =
    
      0
    
      ;
 }
}


    
      void
    
       dfs(
    
      int
    
       x, 
    
      int
    
       y)
{
 
    
      if
    
      (y 
    
      ==
    
       n)
 {
 
    
      if
    
      ( b[x
    
      +
    
      1
    
      ] )
 {
 a[n]
    
      =
    
      x;
 cout
    
      <<
    
      "
    
      1 
    
      "
    
      ;
 
    
      for
    
      (q
    
      =
    
      2
    
      ; q
    
      <=
    
      n; q
    
      ++
    
      )
 {
 cout
    
      <<
    
      a[q];
 
    
      if
    
      (q
    
      !=
    
      n) cout
    
      <<
    
      "
    
       
    
      "
    
      ;
 }
 cout
    
      <<
    
      endl;
 }
 }
 
 
    
      for
    
      (
    
      int
    
       p
    
      =
    
      2
    
      ;p
    
      <=
    
      n;p
    
      ++
    
      )
 
 
    
      if
    
      (b[x
    
      +
    
      p] 
    
      &&
    
       used[p]
    
      ==
    
      0
    
      )
 {
 a[y]
    
      =
    
      x;
 used[p]
    
      =
    
      1
    
      ;
 dfs(p,y
    
      +
    
      1
    
      );
 used[p]
    
      =
    
      0
    
      ;
 }
}

    
      int
    
       main()
{
 Init();
 
    
      int
    
       k
    
      =
    
      0
    
      ;
 
    
      while
    
      (cin
    
      >>
    
      n)
 {
 memset(used, 
    
      0
    
      , 
    
      sizeof
    
      (used));
 used[
    
      1
    
      ]
    
      =
    
      1
    
      ;
 a[
    
      1
    
      ]
    
      =
    
      1
    
      ;
 cout
    
      <<
    
      "
    
      Case 
    
      "
    
      <<++
    
      k
    
      <<
    
      "
    
      :
    
      "
    
      <<
    
      endl;
 dfs(
    
      1
    
      ,
    
      1
    
      );
 cout
    
      <<
    
      endl;
 }
 
    
      return
    
       
    
      0
    
      ;
}