There is also an non-insignificant number of patents that expressly cover an algorithm that would have been found in most computer science textbooks - verbatim

There is also an non-insignificant number of patents that expressly cover an algorithm that would have been found in most computer science textbooks - verbatim - since the '70s. One notable example is the Quicksort algorithm (US 5,175,857). Another is arithmetic coding (known since at least 1976), which has been patented no less than 31 times. If basic information theory can be patented, there's a problem.