=============
= =
= =
= = L
= H =
= =
= =
=============
W
==================
= =
= =
= W = L
= =
= =
==================
H
D[1] = h(1);
D[i] = h(i) + max(D[j] | j < i, we can put block i on top of block j)
Answer is the max element of D.