HDU 4622 Reincarnation 后缀自动机

模板来源：http://blog.csdn.net/zkfzkfzkfzkfzkfzkfzk/article/details/9669747

解法参考：http://blog.csdn.net/dyx404514/article/details/9631787

刚学后缀自动机，还是有很多性质不是很了解……目前也就能做个模板题orz

 #include<cstdio>
 #include<cstring>
 #include<cstdlib>
 #include<algorithm>

 using namespace std;

 #define N 2010
 #define MAXQ 10010

 struct Suffix_Automaton
 {
     int F[N << ],ant,last,ch[N << ][],step[N << ];

     void init()
     {
         last = ant = ;
         memset(F,,sizeof(F));
         memset(ch,,sizeof(ch));
         memset(step,,sizeof(step));
     }

     void ins(int x)
     {
         int t = ++ant, pa = last;
         step[t] = step[last] + ;
         last = t;
         for( ; pa && !ch[pa][x]; pa = F[pa] )
             ch[pa][x] = t;
         if( pa ==  ) F[t] = ;
         else if( step[pa] +  == step[ ch[pa][x] ] )
             F[t] = ch[pa][x];
         else
         {
             int nq = ++ant, q = ch[pa][x];
             memcpy( ch[nq], ch[q], sizeof(ch[nq]) );
             step[nq] = step[pa] + ;
             F[nq] = F[q];
             F[q] = F[t] = nq;
             for( ; pa && ch[pa][x] == q; pa = F[pa] )
                 ch[pa][x] = nq;
         }
     }
 };
 //以上为后缀自动机模板

 struct node
 {
     int l, r;
     int id;
 };

 node qry[MAXQ];
 char str[];
 int ans[MAXQ];
 Suffix_Automaton SAM;

 bool cmp( node a, node b )
 {
     if ( a.l == b.l ) return a.r < b.r;
     return a.l < b.l;
 }

 int main()
 {
     int T;
     scanf( "%d", &T );
     while ( T-- )
     {
         scanf( "%s", &str[] );
         int Q;
         scanf( "%d", &Q );
         for ( int i = ; i < Q; ++i )
         {
             scanf("%d%d", &qry[i].l, &qry[i].r );
             qry[i].id = i;
         }
         sort( qry, qry + Q, cmp );

         int preL = qry[].l;
         SAM.init();
         int j = preL;
         for ( int i = ; i < Q; ++i )
         {
             if ( qry[i].l == preL )
             {
                 while ( j <= qry[i].r )
                 {
                     SAM.ins( str[j] - 'a' );
                     ++j;
                 }
                 int tmp = ;
                 for ( int k = SAM.ant; k > ; --k )
                     tmp += SAM.step[k] - SAM.step[ SAM.F[k] ];
                 ans[ qry[i].id ] = tmp;
             }
             else
             {
                 preL = qry[i].l;
                 j = qry[i].l;
                 SAM.init();
                 while ( j <= qry[i].r )
                 {
                     SAM.ins( str[j] - 'a' );
                     ++j;
                 }
                 int tmp = ;
                 for ( int k = SAM.ant; k > ; --k )
                     tmp += SAM.step[k] - SAM.step[ SAM.F[k] ];
                 ans[ qry[i].id ] = tmp;
             }
         }

         for ( int i = ; i < Q; ++i )
         printf( "%d\n", ans[i] );
     }
     return ;
 }

推荐几篇学习后缀自动机的文章：

陈立杰课件：http://wenku.baidu.com/view/7afa5828ed630b1c59eeb512.html

推荐资料：

http://www.neroysq.com/?p=76

http://fanhq666.blog.163.com/blog/static/8194342620123352232937/

http://hi.baidu.com/myidea/item/142c5cd45901a51820e25039

http://blog.sina.com.cn/s/blog_70811e1a01014dkz.html