ZOJ - 4114 flipping game DP, reasonable state representation

The main idea of the topic :

Here are two lengths for you $n(n\le 100)$ Of 01 character string . You need to $k(k\le 100)$ Wheel operation , Select each operation $m(m\le n)$ Characters , Reverse it .

Ask how many schemes you have to make $k$ After the round, the first string is transformed into the second string .

Topic ideas :

K After the round , Two strings are equal . Then we only need to record the current rounds and several strings are not equal .

So define $dp(i,j)$ For the former $i$ round , The current situation is just $k$ The number of schemes of characters different from the second string .

$dp(i,j-k+m-k)+=C_j^k{C}_{n-j}^{m-k}dp(i-1,j)$