后缀数组，倍增算法

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include

include

include

include

using namespace std ;

char *r = “aabaaaab” ;

const int n = strlen(r) ;

const int m = 256 ;

const int maxn = 300 ;

int wx[maxn],wy[maxn],wv[maxn],w[maxn],sa[maxn] ;

//算法中用到了 计数排序

//wx 与 wy 第一关键字和第二关键字数组（就是图片中表示X和Y的数组）

//wx同时也是rank的值你可以发现x值和rank值是相同的

//由于字符串相等的时候要用相同的排名，需要用上一轮的rank来确定新的rank，所以wx和wy轮流分别作为第一关健数组和第二关键数组

//w是计数排序用到的计数数组

int main()

{

int *x = wx ;

int *y = wy ;

for( int i = 0 ; i < maxn ; ++ i ) wx[i]=wy[i] = -1 ;

for( int i = 0 ; i < m ; ++ i ) w[i] = 0 ;

for( int i = 0 ; i < n ; ++ i ) w[x[i]=r[i]-‘a’]++ ;

for( int i = 1 ; i < m ; ++ i ) w[i] += w[i-1] ;

for( int i = n-1 ; i >=0 ; – i ) sa[–w[x[i]]] = i ;

/*for( int i = 0 ; i < n ; ++ i )
cout<<x[i]+1<<" " ;
cout<<endl ;
for( int i = 0 ; i < n ; ++ i )
cout<<sa[i]<<" " ;
cout<<endl<<"***********"<<endl ;*/

for( int j = 1 ; j < n ; j*=2 )
{
int p = 0 ;
for( int i = n-j ; i < n ; ++ i ) y[p++] = i ;
for( int i = 0 ; i < n ; ++ i ) if( sa[i] >= j ) y[p++] = sa[i]-j ;

for( int i = 0 ; i < n ; ++ i ) wv[i] = x[y[i]] ;
for( int i = 0 ; i < m ; ++ i ) w[i] = 0 ;
for( int i = 0 ; i < n ; ++ i ) w[wv[i]]++ ;
for( int i = 1 ; i < n ; ++ i ) w[i] += w[i-1] ;
for( int i = n-1 ; i >= 0 ; -- i ) sa[--w[wv[i]]] = y[i] ;

p = 1 ;
swap(x,y) ;
x[sa[0]] = 0 ;
for( int i = 1 ; i < n ; ++ i )
x[sa[i]] = y[sa[i]]==y[sa[i-1]] && y[sa[i]+j]==y[sa[i-1]+j]? p-1:p++ ;

/*for( int i = 0 ; i < n ; ++ i )
cout<<x[i]+1<<" " ;
cout<<endl ;
for( int i = 0 ; i < n ; ++ i )
cout<<sa[i]<<" " ;
cout<<endl<<"***********"<<endl ;*/

}

for( int i = 0 ; i < n ; ++ i )
cout<<x[i]+1<<" " ;
cout<<endl ;
for( int i = 0 ; i < n ; ++ i )
cout<<sa[i]<<" " ;
cout<<endl<<"***********"<<
7bbf
endl ;

return 0 ;

}

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