洛谷 P3804 【模板】后缀自动机

来一份模板

 #include<cstdio>
 #include<algorithm>
 #include<cstring>
 #include<queue>
 using namespace std;
 typedef long long LL;
 char s[];
 int n;
 LL ans;
 namespace SAM
 {
     int mem,np,root;
     int len[],par[];
     int trans[][];
     int in[],sz[];
     void append(int ch)
     {
         int p=np;np=++mem;len[np]=len[p]+;
         for(;p&&!trans[p][ch];p=par[p])    trans[p][ch]=np;
         if(!p)    par[np]=root;
         else
         {
             int q=trans[p][ch];
             if(len[q]==len[p]+)    par[np]=q;
             else
             {
                 int nq=++mem;par[nq]=par[q];par[q]=par[np]=nq;
                 memcpy(trans[nq],trans[q],sizeof(trans[nq]));len[nq]=len[p]+;
                 for(;p&&trans[p][ch]==q;p=par[p])    trans[p][ch]=nq;
             }
         }
         sz[np]=;
     }
     void build()
     {
         np=root=++mem;
         for(int i=;i<=n;i++)    append(s[i]-'a');
     }
     queue<int> q;
     void work()
     {
         int i,t;
         for(i=;i<=mem;i++)    ++in[par[i]];
         for(i=;i<=mem;i++)
             if(!in[i])
                 q.push(i);
         while(!q.empty())
         {
             t=q.front();q.pop();
             if(sz[t]>)    ans=max(ans,LL(sz[t])*len[t]);
             if(par[t])
             {
                 sz[par[t]]+=sz[t];
                 --in[par[t]];
                 if(!in[par[t]])    q.push(par[t]);
             }
         }
     }
 }

 int main()
 {
     scanf("%s",s+);n=strlen(s+);
     SAM::build();SAM::work();
     printf("%lld",ans);
     return ;
 }

还有后缀数组强行A此题

 #pragma GCC optimize("Ofast")
 #pragma GCC target("sse3","sse2","sse")
 #pragma GCC target("avx","sse4","sse4.1","sse4.2","ssse3")
 #pragma GCC target("f16c")
 #pragma GCC optimize("inline","fast-math","unroll-loops","no-stack-protector")
 #pragma GCC diagnostic error "-fwhole-program"
 #pragma GCC diagnostic error "-fcse-skip-blocks"
 #pragma GCC diagnostic error "-funsafe-loop-optimizations"
 #pragma GCC diagnostic error "-std=c++14"
 #include<cstdio>
 #include<algorithm>
 #include<cstring>
 #include<map>
 using namespace std;
 char s[];
 int n;
 namespace SA
 {
     int sa[],t1[],t2[],m='z',cnt[],p;
     int *x=t1,*y=t2,*rk=t1,*height=t2;
     template<typename T>
     T get(int pos,T *a)
     {
         return pos<=n?a[pos]:;
     }
     void build()
     {
         int i,k;int *it,*ed;
         for(i=;i<=n;++i)    ++cnt[x[i]=s[i]];
         for(it=cnt+,ed=cnt+m+;it!=ed;++it)    *it+=*(it-);
         for(i=n;i>=;--i)    sa[cnt[x[i]]--]=i;
         for(k=;k<=n;k<<=)
         {
             p=;
             for(i=n-k+;i<=n;++i)    y[++p]=i;
             for(i=;i<=n;++i)    if(sa[i]>k)  y[++p]=sa[i]-k;
             for(it=cnt+,ed=cnt+m+;it!=ed;++it)    *it=;
             for(i=;i<=n;++i)    cnt[x[y[i]]]++;
             for(it=cnt+,ed=cnt+m+;it!=ed;++it)    *it+=*(it-);
             for(i=n;i>=;--i)    sa[cnt[x[y[i]]]--]=y[i];
             swap(x,y);p=;
             for(i=;i<=n;++i)
                 x[sa[i]]=y[sa[i]]==y[sa[i-]]&&get(sa[i]+k,y)==get(sa[i-]+k,y)
                     ?p:++p;
             if(p>=n) break;
             m=p;
         }
         for(i=;i<=n;++i)    rk[sa[i]]=i;
         for(i=,k=;i<=n;++i)
         {
             if(k)   k--;
             if(rk[i])
                 while(get(sa[rk[i]-]+k,s)==get(i+k,s)) k++;
             height[rk[i]]=k;
         }
     }
 }
 int sz[],fa[];
 int find(int x)    {return x==fa[x]?x:fa[x]=find(fa[x]);}
 typedef pair<int,int> P;
 typedef long long LL;
 P tmp[];
 LL ans;
 bool cmp(const P& a,const P& b)
 {
     return a>b;
 }
 int main()
 {
     int i,d,t,fx,fy;
     scanf("%s",s+);n=strlen(s+);SA::build();
     for(i=;i<=n;i++)    fa[i]=i,sz[i]=;
     for(i=;i<=n;i++)    tmp[i]=P(SA::height[i],i);
     sort(tmp+,tmp+n+,cmp);
     for(i=;i<=n;i++)
     {
         d=tmp[i].first;t=tmp[i].second;
         fx=find(t-);fy=find(t);
         sz[fy]+=sz[fx];fa[fx]=fy;
         ans=max(ans,LL(sz[fy])*d);
     }
     printf("%lld",ans);
     return ;
 }

以下是作死用map之后T掉的程序

 #include<cstdio>
 #include<algorithm>
 #include<cstring>
 #include<map>
 #include<queue>
 using namespace std;
 typedef long long LL;
 char s[];
 int n;
 LL ans;
 namespace SAM
 {
     int mem,np,root;
     int len[],par[];
     map<int,int> trans[];
     int in[],sz[];
     void append(int ch)
     {
         int p=np;np=++mem;len[np]=len[p]+;
         for(;p&&!trans[p].count(ch);p=par[p])    trans[p][ch]=np;
         if(!p)    par[np]=root;
         else
         {
             int q=trans[p][ch];
             if(len[q]==len[p]+)    par[np]=q;
             else
             {
                 int nq=++mem;par[nq]=par[q];par[q]=par[np]=nq;
                 trans[nq]=trans[q];len[nq]=len[p]+;
                 for(;p&&trans[p].count(ch)&&trans[p][ch]==q;p=par[p])    trans[p][ch]=nq;
             }
         }
         sz[np]=;
     }
     void build()
     {
         np=root=++mem;
         for(int i=;i<=n;i++)    append(s[i]-'a');
     }
     queue<int> q;
     void work()
     {
         int i,t;
         for(i=;i<=mem;i++)    ++in[par[i]];
         for(i=;i<=mem;i++)
             if(!in[i])
                 q.push(i);
         while(!q.empty())
         {
             t=q.front();q.pop();
             if(sz[t]>)    ans=max(ans,LL(sz[t])*len[t]);
             if(par[t])
             {
                 sz[par[t]]+=sz[t];
                 --in[par[t]];
                 if(!in[par[t]])    q.push(par[t]);
             }
         }
     }
 }

 int main()
 {
     scanf("%s",s+);n=strlen(s+);
     SAM::build();SAM::work();
     printf("%lld",ans);
     return ;
 }