Hi, i am faced with the following 2D segment tree (actually title says) problem on SPOJ. Problem link here: link. Basically it says to find the area of union of rectangles. Number of rectangles is up to 10^5. Is it possible to solve this problem using 2D segment tree + lazy propagation?. I read about quadtrees, but it's written complexity of per operation in Quadtrees is O(N). Can you give any hint to solve this problem?