Concepts: Basic Geometry
Problem Link: http://www.codechef.com/CRNM2014/problems/CRANCRD
Johny measures the distance between P1(x1,y1) and P2(x2,y2) as :
D(P1,P2) = |x1 - x2| + |y1 – y2|
A circle according to Johny’s understanding will actually be a square with diagonals parallel to the x and y axes.
Follow the second page of this doc for a pictorial explanation.
Hence the answer is 2*r^2.