Agreed, I, too, had the feeling that he didn't get the algorithm. In fact, you have to compare every 5th position with all 5 letters of the pattern - p, e, n, 1

Agreed, I, too, had the feeling that he didn't get the algorithm. In fact, you have to compare every 5th position with all 5 letters of the pattern - p, e, n, 1 and s, (edit) or the other way around, like you said, which can be done nicely by using character sets like in Pascal or bitmaps in C++. Which brings up a question whether this method is any better than, for example, the Intel x86 instruction for linearly scanning strings (the SCAS family, if I'm not mistaken).