poj 2406 D3C 算法 后缀数组 连续重复子串

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>

using namespace std;
const int MAXN=10000005;
int r[MAXN],lcp[MAXN];
char s[MAXN];
#define F(x) ((x)/3+((x)%3==1?0:tb))
#define G(x) ((x)<tb?(x)*3+1:((x)-tb)*3+2)
int wa[MAXN],wb[MAXN],wv[MAXN],sa[MAXN];
int wws[MAXN];
int c0(int *r,int a,int b)
{return r[a]==r[b]&&r[a+1]==r[b+1]&&r[a+2]==r[b+2];}
int c12(int k,int *r,int a,int b)
{if(k==2) return r[a]<r[b]||r[a]==r[b]&&c12(1,r,a+1,b+1);
else return r[a]<r[b]||r[a]==r[b]&&wv[a+1]<wv[b+1];}
void sort(int *r,int *a,int *b,int n,int m)
{
int i;
for(i=0;i<n;i++) wv[i]=r[a[i]];
for(i=0;i<m;i++) wws[i]=0;
for(i=0;i<n;i++) wws[wv[i]]++;
for(i=1;i<m;i++) wws[i]+=wws[i-1];
for(i=n-1;i>=0;i--) b[--wws[wv[i]]]=a[i];
return;
}
void dc3(int *r,int *sa,int n,int m)
{
int i,j,*rn=r+n,*san=sa+n,ta=0,tb=(n+1)/3,tbc=0,p;
r
=r[n+1]=0;
for(i=0;i<n;i++) if(i%3!=0) wa[tbc++]=i;
sort(r+2,wa,wb,tbc,m);
sort(r+1,wb,wa,tbc,m);
sort(r,wa,wb,tbc,m);
for(p=1,rn[F(wb[0])]=0,i=1;i<tbc;i++)
rn[F(wb[i])]=c0(r,wb[i-1],wb[i])?p-1:p++;
if(p<tbc) dc3(rn,san,tbc,p);
else for(i=0;i<tbc;i++) san[rn[i]]=i;
for(i=0;i<tbc;i++) if(san[i]<tb) wb[ta++]=san[i]*3;
if(n%3==1) wb[ta++]=n-1;
sort(r,wb,wa,ta,m);
for(i=0;i<tbc;i++) wv[wb[i]=G(san[i])]=i;
for(i=0,j=0,p=0;i<ta && j<tbc;p++)
sa[p]=c12(wb[j]%3,r,wa[i],wb[j])?wa[i++]:wb[j++];
for(;i<ta;p++) sa[p]=wa[i++];
for(;j<tbc;p++) sa[p]=wb[j++];
return;
}
int rank[MAXN]; //index range 0~n-1 value range 1~n
int height[MAXN]; //index from 1   (height[1] = 0)
void calheight(int *r, int *sa, int n)
{
int i, j, k = 0;
for (i = 1; i <= n; ++i) rank[sa[i]] = i;
for (i = 0; i < n; height[rank[i++]] = k)
for (k ? k-- : 0, j = sa[rank[i] - 1]; r[i + k] == r[j + k]; ++k);
return;
}

int main()
{
// freopen("//media/学习/ACM/input.txt","r",stdin);
while (~scanf("%s",s),s[0]!='.')
{
int i,j,len;
int n=strlen(s);
for (i=0;i<n;i++)
{
r[i]=s[i]-'a'+1;
lcp[i]=0;
}r
=0;
dc3(r, sa, n+1 ,n+2);
calheight(r, sa, n);
lcp[rank[0]]=1<<29;
for (i=rank[0]-1;i>=0;i--) lcp[i]=min(lcp[i+1],height[i+1]);
for (i=rank[1]+1;i<=n;i++) lcp[i]=min(lcp[i-1],height[i]);
for (len=1;len<=n;len++)
if (n % len==0&&lcp[rank[len]]==n-len)
{
printf("%d\n",n / len);
break;
}
}
}