KMP (Algorithm Description)

#include <the iostream> the using namespace STD; const int N = 10010 , M = 100010 ;
 int n-, m;
 char P [N], S [M];
 int NE [N]; int main () 
{ 
    CIN >> n- >> P + . 1 >> m >> S + . 1 ;
     // find next: for short arrays for ( int I = 2 , J = 0 ; I <= n-; I ++ ) 
    { the while (J && P [I] = P! [+ J . 1 ]) J = NE [J]; // the no match, an array of short matches start from the same position of the front edge of IF (P [I] == P [J +

 

 


    
        
        1])j++;
        ne[i]=j;
    }
    //kmp匹配
    for(int i=1,j=0;i<=m;i++)
    {
        while(j&&s[i]!=p[j+1])j=ne[j];
        if(s[i]==p[j+1])j++;
        if(j==n)//匹配成功
        {
            cout<<i-n<<' ';
            j=ne[j];
        }
    }
    return  0;
}

Be optimized by reducing the same string matching

Focus is on next array Seeking

 

j: an array is small, the matching process is performed, the comparison is the same whether the j + 1, j + 1 when the same is not to replace a position j has small front array matching, i.e., the corresponding value in the next.