During the covid-19 pandemic, the capacity of testing facilities and the possibilities to increase it were often discussed. One of the methods that was actually implemented in practice was pooling.
This is a method where multiple samples are mixed and tested at the same time. In practice, pooling was used in such a way that the test took place in two steps.
In the first step, small groups of samples were tested (according to the recommendations of the MZČR, the size of 6-10 samples). If any group was positive, each sample of that group was tested separately in a second step.
In this article, we will present methods of group testing (Combinatorial group testing), which stand on the border between mathematics and informatics and which enable the detection of specific infected samples directly in the first step of the test. The presented algorithms are available to high school students and mainly use the properties of writing a number in a system with a different base.