Calculate the perimeter and area of intersecting rectangles?

Question

I searched a lot, but I didn\'t find a good answer that works for this case. We have some rectangles that are horizontal or vertical. They can be placed on the page randomly

Answer 1

The following is O(N2) solution.

int area = 0;
FOR(triange=0->N)
{
    Area = area trianlges[triangle];
    FOR(int j = triangle+1 -> N)
    {
        area-= inter(triangle , j)
    }
}
return area;

int inter(tri a,tri b)
{
    if ( ( min(a.highY ,b.highY) > max(a.lowerY, b.lowerY) ) && ( min(a.highX ,b.highX) > max(a.lowerX, b.lowerX) ) )
    return ( min(a.highY ,b.highY) - max(a.lowerY, b.lowerY) ) * ( min(a.highX ,b.highX) - max(a.lowerX, b.lowerX) )

    else return 0;
}