Z - algorithm function
static int [ ] z_function ( char [ ] s ) { int n = s . length ; int [ ] z = new int [ n ] ; for ( int i = 1 , l = 0 , r = 0 ; i < n ; i ++ ) { if ( i <= r ) z [ i ] = Math . min ( r - i + 1 , z [ i - l ] ) ; while ( i + z [ i ] < n && s [ z [ i ] ] == s [ i + z [ i ] ] ) z [ i ] ++ ; if ( i + z [ i ] - 1 > r ) { l = i ; r = i + z [ i ] - 1 ; } } return z ; } static int n , len = 0 ;