Introduction - If you have any usage issues, please Google them yourself
Classic dynamic compression DP, status is f[i][j], that the first line i to j for the 3-band status. j representatives of a lattice, can only be: 0 indicated that the first i rows and the first i- 1 line no artillery, the first one that i did not artillery line the first i-1 lines have artillery, line 2 that the first i have artillery