SRM 570 div2

250,500 is relatively simple, and 1000 is started after completion

It is found that 1000pt is a counting question similar to the tree-like DP. Ask you to select the total number of several vertices from the tree with 50 nodes. These vertices must be connected.

DP [I] [J] indicates the number of sub-trees with I as the root, connected to the number of solutions for J points, and then it is OK to write two loops and make a backpack.

PS: There are only half an hour left after writing three questions. I want to construct some data to prepare x persons. However, the question is too simple to start. In the end, our room was very harmonious and there was no event of X persons.

Rank 8 souvenir