Number of contacts between a group of 2-D circles

Specifically, write a Matlab function file called contact.m that takes in as an input the X-Y position and radius of a collection of circles as a single (3xN or Nx3) variable. The function should output (in this order)(1) the total number of overlapping circles (contacts), (2) the average number of contacts per circle and (3) the standard deviation of contacts.

Note the input variable may be a 3xN or Nx3 array and so your function should be able to detect and still work for both cases.