后缀数组

Power Strings

#include <stdio.h>
#include <iostream>
#include <algorithm>
#include <string.h>
#include <queue>
#include <vector>
#include <map>
#include <cmath>
#include <stack>
#define F(x) ((x)/3+((x)%3==1?0:tb))
#define G(x) ((x)<tb?(x)*3+1:((x)-tb)*3+2)
using namespace std;
const int MAXN = 1000105;
const int inf = 1000000007;
int wa[MAXN*3],wb[MAXN*3],wv[MAXN*3],wss[MAXN*3];
int sa[MAXN*3],Rank[MAXN*3],height[MAXN*3],r[MAXN*3];
char s[MAXN*3];
int query[MAXN*3];

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++){
        wss[i]=0;
    }
    for(i=0;i<n;i++){
        wss[wv[i]]++;
    }
    for(i=1;i<m;i++){
        wss[i]+=wss[i-1];
    }
    for(i=n-1;i>=0;i--){
        b[--wss[wv[i]]]=a[i];
    }
}

void dc3(int *r,int *sa,int n,int m){
    int i,j,*rn=r+n;
    int *san=sa+n,ta=0,tb=(n+1)/3,tbc=0,p;
    r[n]=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(int 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++];
    }
}
void getheight(int *r,int *sa,int n)
{
    int i,j,k=0;
    for(i=0; i<n; i++)
        r[i]=s[i];
    r[i]=0;
    dc3(r,sa,n+1,128);
    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++);
}
 
int main()
{
    while(scanf("%s",s))
    {
        if(!strcmp(s,".")){
            break;
        }
        int n=strlen(s);
        getheight(r,sa,n);
        query[Rank[0]]=inf;
        int i;
        for(i=Rank[0]-1; i>=1; i--)
            query[i]=min(height[i+1],query[i+1]);
        for(i=Rank[0]+1; i<=n; i++)
            query[i]=min(height[i],query[i-1]);
        for(i=1; i<=n; i++)
            if(n%i==0&&query[Rank[i]]==n-i)
                break;
        printf("%d
",n/i);
    }
    return 0;
}