【POJ1743】不可重叠最长重复子串

　　题意：求一个字符串里两个不重叠的最长重复子串

代码如下：

 #include<cstdio>
 #include<cstdlib>
 #include<cstring>
 #include<iostream>
 using namespace std;

 int sa[],rank[],y[],Rsort[];
 int wr[],a[],height[],n;

 bool cmp(int k1,int k2,int ln){return wr[k1]==wr[k2] && wr[k1+ln]==wr[k2+ln];}

 void get_sa(int m)
 {
   int i,k,p,ln;

   memcpy(rank,a,sizeof(rank));

   memset(Rsort,,sizeof(Rsort));
   for (i=;i<=n;i++) Rsort[rank[i]]++;
   for (i=;i<=m;i++) Rsort[i]+=Rsort[i-];
   for (i=n;i>=;i--) sa[Rsort[rank[i]]--]=i; 

   ln=; p=;
   while (p<n)
   {
       for (k=,i=n-ln+;i<=n;i++) y[++k]=i;
       for (i=;i<=n;i++) if (sa[i]>ln) y[++k]=sa[i]-ln;
       for (i=;i<=n;i++) wr[i]=rank[y[i]];

       memset(Rsort,,sizeof(Rsort));
       for (i=;i<=n;i++) Rsort[wr[i]]++;
       for (i=;i<=m;i++) Rsort[i]+=Rsort[i-];
       for (i=n;i>=;i--) sa[Rsort[wr[i]]--]=y[i];

       memcpy(wr,rank,sizeof(wr));
       p=; rank[sa[]]=;
       for (i=;i<=n;i++)
       {
          if (!cmp(sa[i],sa[i-],ln)) p++;
          rank[sa[i]]=p;
       }
       m=p; ln*=;
   }
   a[]=sa[]=;
 }

 void get_he()
 {
   int i,j,k=;
   for (i=;i<=n;i++)
   {
      j=sa[rank[i]-];
      if (k) k--;

      while (a[j+k]==a[i+k]) k++;
      height[rank[i]]=k;
   }
 }

 bool check(int k)
 {
     int i,maxx=,minn=;
     for(i=;i<=n;i++)
     {
         if(height[i]<k) maxx=minn=sa[i];
         else
         {
             if(sa[i]>maxx) maxx=sa[i];
             if(sa[i]<minn) minn=sa[i];
             if(maxx-minn>k) return ;
         }
     }
     return ;
 }

 int hd_work()
 {
     int l,r,mid,ans=;
     l=;r=n;
     while(l<=r)
     {
         mid=(l+r)/;
         if(check(mid))
         {
           l=mid+;
           ans=mid;
         }
         else r=mid-;
     }
     if(ans>=) ans++;
     else ans=;
     return ans;
 }

 int main()
 {
     int i,a1,a2;
     while()
     {
         scanf("%d",&n);
         if(n==) break;
         scanf("%d",&a1);
         for(i=;i<=n;i++)
         {
             scanf("%d",&a2);
             a[i-]=a2-a1+;
             a1=a2;
         }
         n--;
         get_sa();
         get_he();
         printf("%d\n",hd_work());
     }
 }

poj1743

2015-12-15 17:09:09