[Codevs 1995] the door to the black magician (and query set)

Title: http://codevs.cn/problem/1995/

Analysis: the subgraph that satisfies the requirements of the question must be a ring ...... Then the question becomes the number of rings that are constantly added to the edge. It looks a little troublesome ...... But the essence of the ring is the combination of several small rings ...... So we only need to know the number of the most basic rings. According to the binary theorem, It is 2 ^ (the number of the most basic rings)-1. It's still hard to do !!!!!!

It doesn't matter ...... And found ......

Assuming that the final answer to the I-1 operation is ans, there are two scenarios for the I operation:

① If a new ring does not appear after this edge is added, it indicates that the result is not affected and the result is still ans.

② After this edge is added, a new ring appears. So for the previous ans ring, we can help this new ring to put in a combination as a new ring, so ans * 2, but note that we have a new basic ring, so ans = ans * 2 + 1

So the perfect solution ......

[Codevs 1995] the door to the black magician (and query set)