Update Peaks logic to avoid extra loops

[pankaj-a-khandelwal-db]

Max number of blocks can't exceed peaks count, so that all have at least 1 peak. This also avoids looping when there are no peaks.

[TomaszSowa]

The variable N is used in other calculations, so it must be N = A.length;
But you can start the loop according to your idea:
for(int numBlocks = peaksIndexList.size(); numBlocks > 0; numBlocks--) {