bitmask dp

The link of essay:
https://github.com/Aaron19960821/icpcarchive/blob/master/essayFromNationTeam/动态规划之状态压缩.pdf

Bitmask is a very important technique to divide a huge problem into smaller ones to ensure they are independent from each other. After reading the essay from Chou Wei on the train, I acquired more understanding of this topic.

What we have to do

• We have to make sure the definition of the problems.
• We have to know if one situation can transform to another one.(Usually we use bitmask calculation).
• We do not always use binary to represent our problem, other methods is welcomed if it is necessary.
• We use this method when the problem is referring to conbination rather than permutation.
  Sample problems in this essay
  poj1185
  poj2411
  poj2441
  poj2663