Recently, I have approached this problem : http://orac.amt.edu.au/cgi-bin/train/problem.pl?set=aic00&problemid=12. TLDR : You are given a 2D plane ( with given size W * H ), your job is to place pictures into that plane given the order of pictures such that every picture is always placed at the leftmost and lowest position (not overlapping others). In the end, you have to print the coordinates of the lower-left corner of each picture. I have been thinking of using something like 2D Segment Tree and I'm curious if there is any simpler approach to this problem. Thanks in advance !.