POJ 1321 棋盘问题

解题思路:DFS

代码

   
     

    
      
    
      #include 
    
      <
    
      iostream
    
      >
    
      

    
      using
    
       
    
      namespace
    
       std;

    
      char
    
       chess[
    
      8
    
      ][
    
      9
    
      ];

    
      int
    
       n, m;
inline 
    
      bool
    
       IsOk(
    
      int
    
       i, 
    
      int
    
       j)
{
 
    
      int
    
       k;
    
      bool
    
       istrue
    
      =
    
      true
    
      ;
 
    
      for
    
      (k
    
      =
    
      0
    
      ;k
    
      <
    
      i 
    
      &&
    
       istrue;k
    
      ++
    
      )
 
    
      if
    
      (chess[k][j]
    
      ==
    
      '
    
      *
    
      '
    
      )istrue 
    
      =
    
       
    
      false
    
      ;
 
    
      return
    
       istrue;
}

    
      int
    
       DFS(
    
      int
    
       layer, 
    
      int
    
       k)
{
 
    
      if
    
      (k
    
      ==
    
      0
    
      )
    
      return
    
       
    
      1
    
      ;
 
    
      if
    
      (n
    
      -
    
      layer
    
      +
    
      1
    
      <
    
      k)
    
      return
    
       
    
      0
    
      ;
 
    
      int
    
       i,d
    
      =
    
      0
    
      ;
 
    
      for
    
      (i
    
      =
    
      0
    
      ;i
    
      <
    
      n;i
    
      ++
    
      )
 {
 
    
      if
    
      (chess[layer
    
      -
    
      1
    
      ][i]
    
      ==
    
      '
    
      #
    
      '
    
      &&
    
      IsOk(layer
    
      -
    
      1
    
      , i))
 {
 chess[layer
    
      -
    
      1
    
      ][i]
    
      =
    
      '
    
      *
    
      '
    
      ;
 d 
    
      +=
    
       DFS(layer
    
      +
    
      1
    
      ,k
    
      -
    
      1
    
      );
 chess[layer
    
      -
    
      1
    
      ][i]
    
      =
    
      '
    
      #
    
      '
    
      ;
 }
 }
 d 
    
      +=
    
       DFS(layer
    
      +
    
      1
    
      , k);
 
    
      return
    
       d;
}


    
      int
    
       main()
{
 
    
      int
    
       i, ans;
 
    
      while
    
      (scanf(
    
      "
    
      %d %d
    
      "
    
      , 
    
      &
    
      n, 
    
      &
    
      m) 
    
      &&
    
       
    
      !
    
      (n
    
      ==-
    
      1
    
      &&
    
      m
    
      ==-
    
      1
    
      ))
 {
 
    
      for
    
      (ans 
    
      =
    
       i 
    
      =
    
       
    
      0
    
      ;i 
    
      <
    
       n;i
    
      ++
    
      )scanf(
    
      "
    
      %s
    
      "
    
      ,chess[i]);
 ans 
    
      =
    
       DFS(
    
      1
    
      , m);
 printf(
    
      "
    
      %d\n
    
      "
    
      , ans);
 }
 
    
      return
    
       
    
      0
    
      ;
}