Hi , So I was trying this E problem which was 900 points ,

This problem requires rotation of axes and I know how that is done and also know all the details behind that ,

But the editorial says "rotate the axes by 45 degrees and then find maximum of ... " . . I was not able to follow the EDITORIAL from that point onwards!

I believe this is a nice GEOMETRY problem and I am weak at it ,

Please open this problem and help me know what that one line means , "Now we are intersted in a pair of points such that max ( dx, dy ) = D"

Thankyou!

Here's a hint — Suppose you have a point (x, y). After rotating by 45 degrees, what does it become ?