Here is te problem were it says that: just print YES if AxB=C where A,B,C are nxn matrices. so the apporoach was to multiply C and B w matrix D which it’s size is nx1 so the operiations could be faster AxBxD= CxD. My question comes here, while choosing the values D it must be choosed by math.random otherwise it will fail in one of tests. Could anyone say why?