POJ 3349 Snowflake Snow Snowflakes

解题思路:hash

完整C++代码

   
     

    
      
    
      #include 
    
      <
    
      iostream
    
      >
    
      

    
      using
    
       
    
      namespace
    
       std;

    
      #define
    
       MAX_N 87719
    
      


    
      struct
    
       node{
 node():next(
    
      0
    
      ){}
 
    
      int
    
       arm[
    
      6
    
      ];
 node 
    
      *
    
      next;
}snow[MAX_N];


    
      int
    
       main()
{
 
    
      int
    
       hash,n,i,j,k,t[
    
      6
    
      ];
 node 
    
      *
    
      cur,
    
      *
    
      pre;
 
    
      bool
    
       isFind;
 scanf(
    
      "
    
      %d
    
      "
    
      , 
    
      &
    
      n);
 
    
      for
    
       (i
    
      =
    
      0
    
      ,isFind
    
      =
    
      false
    
      ;i
    
      <
    
      n;i
    
      ++
    
      )
 {
 scanf(
    
      "
    
      %d %d %d %d %d %d
    
      "
    
      ,t,t
    
      +
    
      1
    
      ,t
    
      +
    
      2
    
      ,t
    
      +
    
      3
    
      ,t
    
      +
    
      4
    
      ,t
    
      +
    
      5
    
      );
 
    
      if
    
      (isFind)
    
      continue
    
      ;
 hash 
    
      =
    
       (t[
    
      0
    
      ]
    
      ^
    
      t[
    
      1
    
      ]
    
      ^
    
      t[
    
      2
    
      ]
    
      ^
    
      t[
    
      3
    
      ]
    
      ^
    
      t[
    
      4
    
      ]
    
      ^
    
      t[
    
      5
    
      ])
    
      %
    
      MAX_N;
 cur
    
      =
    
      snow[hash].next;pre
    
      =&
    
      snow[hash];
 
    
      while
    
       (cur
    
      &&!
    
      isFind)
 {
 
    
      for
    
       (j
    
      =
    
      0
    
      ;(j
    
      <
    
      6
    
      )
    
      &&!
    
      isFind;j
    
      ++
    
      )
 {
 
    
      for
    
      (k
    
      =
    
      0
    
      ;k
    
      <
    
      6
    
      ;k
    
      ++
    
      )
 
    
      if
    
      (t[(k
    
      +
    
      j)
    
      %
    
      6
    
      ]
    
      !=
    
      cur
    
      ->
    
      arm[k])
    
      break
    
      ;
 
    
      if
    
      (k
    
      ==
    
      6
    
      ){isFind
    
      =
    
      true
    
      ;
    
      break
    
      ;}
 
    
      for
    
      (k
    
      =
    
      0
    
      ;k
    
      <
    
      6
    
      ;k
    
      ++
    
      )
 
    
      if
    
      (t[(
    
      6
    
      +
    
      j
    
      -
    
      k)
    
      %
    
      6
    
      ]
    
      !=
    
      cur
    
      ->
    
      arm[k])
    
      break
    
      ;
 
    
      if
    
      (k
    
      ==
    
      6
    
      )isFind
    
      =
    
      true
    
      ;
 }
 pre
    
      =
    
      cur,cur
    
      =
    
      cur
    
      ->
    
      next;
 }
 
    
      if
    
      (
    
      !
    
      isFind){node 
    
      *
    
      temp
    
      =
    
      new
    
       node();memcpy(temp
    
      ->
    
      arm,t,
    
      sizeof
    
      (t));pre
    
      ->
    
      next
    
      =
    
      temp;}
 }
 isFind 
    
      ?
    
       printf(
    
      "
    
      Twin snowflakes found.\n
    
      "
    
      ):printf(
    
      "
    
      No two snowflakes are alike.\n
    
      "
    
      );
 
    
      return
    
       
    
      0
    
      ;
}