Misleading comment in the book for Rabin Karp algorithm about tryalgo HOT 4 CLOSED

Hello Florian Courtial, yes good point, DOMAIN*PRIME should be small enough such that the sum stays within 63 bits. So that's why we choose PRIME less than 2^56. This way DOMAIN*PRIME is less than 2^63. old_val is less than 2^53. In fact, PRIME + DOMAIN * PRIME > 2^63. Does not sound good, but since both terms in the sum are less than 2^63, the sum is less than 2^64, so the sign bit is not set in C++, and this number remains positive. We are good. But if the number becomes negative we are in big trouble I think. Because <https://stackoverflow.com/questions/11720656/modulo-operation-with-negative-numbers/42131603> in C++ the modulo of a negative number is negative, and that is not what we want. Christoph