POJ 2513 Colored Sticks

解题思路:trie树+并查集（判断是否属于同一集合）+欧拉通路判断

代码

   
     

    
      
    
      #include 
    
      <
    
      iostream
    
      >
    
      

    
      using
    
       
    
      namespace
    
       std;

    
      #define
    
       MAXN 5000001
    
      

    
      #define
    
       MAXM 500001
    
      

    
      char
    
       ch1[
    
      11
    
      ],ch2[
    
      11
    
      ],trie[MAXN];

    
      int
    
       size,first[MAXN],next[MAXN],place[MAXN];

    
      int
    
       n,root[MAXM],deg[MAXM];


    
      int
    
       find(
    
      int
    
       x)
{
 
    
      if
    
      (root[x]
    
      !=
    
      x)root[x]
    
      =
    
      find(root[x]);
 
    
      return
    
       root[x];
}

    
      int
    
       insert(
    
      char
    
       ch[])
{
 
    
      int
    
       i, t, p
    
      =
    
      0
    
      ,l
    
      =
    
      strlen(ch);
 
    
      for
    
      (i
    
      =
    
      0
    
      ;i
    
      <
    
      l;i
    
      ++
    
      )
 {
 t
    
      =
    
      first[p];
 
    
      while
    
       (t
    
      &&
    
      trie[t]
    
      !=
    
      ch[i])t
    
      =
    
      next[t];
 
    
      if
    
      (
    
      !
    
      t)
 {
 trie[
    
      ++
    
      size]
    
      =
    
      ch[i],next[size]
    
      =
    
      first[p];
 first[p]
    
      =
    
      size,first[size]
    
      =
    
      0
    
      ,p
    
      =
    
      size;
 }
 
    
      else
    
       p
    
      =
    
      t;
 }
 
    
      if
    
      (
    
      !
    
      place[p])place[p]
    
      =++
    
      n;
 
    
      return
    
       place[p];
}

    
      int
    
       main()
{
 
    
      int
    
       i,r1,r2,r,odd;
 
    
      bool
    
       IsOk;
 
    
      for
    
      (i
    
      =
    
      0
    
      ;i
    
      <
    
      MAXM;i
    
      ++
    
      )root[i]
    
      =
    
      i;
 size
    
      =
    
      n
    
      =
    
      0
    
      ;
 
    
      while
    
      (scanf(
    
      "
    
      %s%s
    
      "
    
      , ch1, ch2)
    
      !=
    
      EOF)
 {
 r1
    
      =
    
      insert(ch1),r2
    
      =
    
      insert(ch2);
 deg[r1]
    
      ++
    
      ,deg[r2]
    
      ++
    
      ;
 r1
    
      =
    
      find(r1),r2
    
      =
    
      find(r2);
 
    
      if
    
      (r1
    
      !=
    
      r2)root[r2]
    
      =
    
      r1;
 }
 
    
      for
    
       (IsOk
    
      =
    
      i
    
      =
    
      1
    
      ,r
    
      =
    
      find(
    
      1
    
      ),odd
    
      =
    
      0
    
      ;i
    
      <
    
      n
    
      &&
    
      IsOk;i
    
      ++
    
      )
 {
 
    
      if
    
      (root[i]
    
      ==
    
      i
    
      &&
    
      i
    
      !=
    
      r)IsOk
    
      =
    
      false
    
      ;
 
    
      if
    
      (deg[i]
    
      %
    
      2
    
      ){odd
    
      ++
    
      ;
    
      if
    
      (odd
    
      >
    
      2
    
      )IsOk
    
      =
    
      false
    
      ;}
 }
 IsOk
    
      ?
    
      printf(
    
      "
    
      Possible\n
    
      "
    
      ):printf(
    
      "
    
      Impossible\n
    
      "
    
      );
 
    
      return
    
       
    
      0
    
      ;
}