题目大意:求严格/非严格K小子串
首先建立Sam
然后BFS一遍求出每个点代表状态的出现次数
此时如果是严格的那么每个点代表状态的出现次数都应该是1
然后DFS一遍求出每个节点的后继状态个数
然后就随便搞了啊= =
妈了个鸡卡常数。。。
<code class="language-c++ hljs perl has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">#include <cstdio></span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">#include <cstring></span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">#include <iostream></span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">#include <algorithm></span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">#define M 500500</span>
using namespace std;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> type,k;
char <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">s</span>[M],ans[M];<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> tot;
namespace Suffix_Automaton{
struct Sam{
Sam <span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">*son</span>[<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">26</span>],<span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">*parent</span>;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> max_dpt,cnt;
long long size;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> v;
void* operator new (size_t,<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">_</span>)
{
static Sam mempool[M<<<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>],<span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">*C</span>=mempool;
C->max_dpt=<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">_</span>;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> C++;
}
}<span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">*root</span>=new (<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>)Sam,<span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">*last</span>=root;
void Extend(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">x</span>)
{
Sam <span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">*p</span>=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">last</span>;
Sam <span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">*np</span>=new (p->max_dpt+<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>)Sam;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span>(;p&&!p->son[<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">x</span>];p=p->parent)
p->son[<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">x</span>]=np;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span>(!p)
np->parent=root;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span>
{
Sam <span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">*q</span>=p->son[<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">x</span>];
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span>(p->max_dpt+<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>==<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">q</span>->max_dpt)
np->parent=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">q</span>;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span>
{
Sam <span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">*nq</span>=new (p->max_dpt+<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>)Sam;
memcpy(nq->son,<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">q</span>->son,sizeof nq->son);
nq->parent=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">q</span>->parent;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">q</span>->parent=nq;np->parent=nq;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span>(;p&&p->son[<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">x</span>]==<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">q</span>;p=p->parent)
p->son[<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">x</span>]=nq;
}
}
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">last</span>=np;
}
void BFS()
{
static Sam <span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">*q</span>[M<<<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>];
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> i,r=<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>,h=<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>;
<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">q[++r]</span>=root;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">while</span>(r!=h)
{
Sam <span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">*p</span>=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">q[++h]</span>;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span>(i=<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>;i<<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">26</span>;i++)
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span>(p->son[i]&&p->son[i]->v!=<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>)
p->son[i]->v=<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>,<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">q[++r]</span>=p->son[i];
}
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span>(i=r;i>=<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2</span>;i--)
{
Sam <span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">*p</span>=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">q[i]</span>;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span>(type==<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>)
p->cnt=(bool)p->cnt;
p->parent->cnt+=p->cnt;
}
}
void DFS(Sam <span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">*p</span>)
{
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> i;
p->v=<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2</span>;
p->size=p->cnt;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span>(i=<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>;i<<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">26</span>;i++)
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span>(p->son[i])
{
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span>(p->son[i]->v!=<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2</span>)
DFS(p->son[i]);
p->size+=p->son[i]->size;
}
}
void Get_Kth(Sam <span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">*p</span>,<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> k)
{
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> i;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span>(k<=p->cnt)
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> ;
k-=p->cnt;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span>(i=<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>;i<<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">26</span>;i++)
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span>(p->son[i])
{
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span>(k<=p->son[i]->size)
{
ans[++tot]=i+<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'a'</span>;
Get_Kth(p->son[i],k);
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> ;
}
k-=p->son[i]->size;
}
}
}
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> main()
{
using namespace Suffix_Automaton;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> i;
scanf(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"<span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">%s</span><span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">%d</span><span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">%d</span>"</span>,<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">s</span>+<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>,&type,&k);
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span>(i=<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">s</span>[i];i++)
{
Extend(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">s</span>[i]-<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'a'</span>);
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">last</span>->cnt++;
}
BFS();root->cnt=<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>;
DFS(root);
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span>(root->size<k)
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> cout<<-<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span><<endl,<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>;
Get_Kth(root,k);
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">printf</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"<span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">%s</span>\n"</span>,ans+<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>);
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>;
}</code>
本文介绍了一种使用后缀自动机(SAM)解决求字符串中严格/非严格K小子串问题的方法。首先构建SAM,接着通过BFS计算各状态出现次数,并用DFS计算节点后继状态数。
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