CF342E.Xenia and Tree
普及/提高-
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题目描述
Xenia the programmer has a tree consisting of n nodes. We will consider the tree nodes indexed from 1 to n . We will also consider the first node to be initially painted red, and the other nodes — to be painted blue.
The distance between two tree nodes v and u is the number of edges in the shortest path between v and u .
Xenia needs to learn how to quickly execute queries of two types:
- paint a specified blue node in red;
- calculate which red node is the closest to the given one and print the shortest distance to the closest red node.
Your task is to write a program which will execute the described queries.
输入格式
The first line contains two integers n and m (2<=n<=105,1<=m<=105) — the number of nodes in the tree and the number of queries. Next n−1 lines contain the tree edges, the i -th line contains a pair of integers ai,bi (1<=ai,bi<=n,ai=bi) — an edge of the tree.
Next m lines contain queries. Each query is specified as a pair of integers ti,vi (1<=ti<=2,1<=vi<=n) . If ti=1 , then as a reply to the query we need to paint a blue node vi in red. If ti=2 , then we should reply to the query by printing the shortest distance from some red node to node vi .
It is guaranteed that the given graph is a tree and that all queries are correct.
输出格式
For each second type query print the reply in a single line.
输入输出样例
输入#1
5 4 1 2 2 3 2 4 4 5 2 1 2 5 1 2 2 5
输出#1
0 3 2