Take the tour ×  There is an old dry well. Its sides are made of
concrete rings. Each such ring is one meter high, but the rings
can have different (internal) diameters. Nevertheless, all the
rings are centered on one another. The well is N meters deep;
that is, there are N concrete rings inside it. You are about to
drop M concrete disks into the well. Each disk is one meter
thick, and different disks can have different diameters. Once
each disk is dropped, it falls down until:    • it hits the
bottom of the well;   • it hits a ring whose internal diameter
is smaller then the disk's diameter; or   • it hits a previously
dropped disk. (Note that if the internal diameter of a ring and
the diameter of a disk are equal, then the disk can fall through
the ring.)  The disks you are about to drop are ready and you
know their diameters, as well as the diameters of all the rings
in the well. The question arises: how many of the disks will fit
into the well?  Write a function: int falling_disks(int A[], int
N, int B[],