A had two solutions. (The same optimizations BUT)
In the first one I sorted rows' lengths in increasing order. It got TL 24.
In the second one I sorted rows' lengths in decreasing order. It got TL 17.
I've connected both solutions and have got AC in 0.062 !!!

Your solution is truly AC!
I tried 2000000 or random tests and your solution passed all. By the way, your way of solving differs from mine.