Hello, I'm doing this problem, the statement is in Vietnamese, therefore I'll give you a summary:

Given n rectangles on a 2D coordination (x, y, w, h), two rectangles are connected if any of it's edges touches, find the largest connected rectangles area (w, h <= 500), no rectangles overlaps with each other and each rectangle is (x, y, x + w, y + h)

The editorial suggested using DSU combined with sweep line, however I'm still not clear on it, I'd appreciate some help, thanks!