-
A tree on $N$ nodes labeled with integers between $0$ and $N-1$ is given. Initially, all nodes are white, except node $0$ which is black. Your task is to answer two types of queries:
-
Type $0$: given node $u$, change the color of node $u$ from white to black
-
Type $1$: given node $u$, print the distance between $u$ and the black node furthest away, measured in number of crossed edges
If a node is given in a query of type $0$, it is guaranteed to be white at that point in time.
Input
The first line of input contains the integers $N$ and $Q$ ($1 \leq N,Q \leq 2*10^5$), the number of nodes and queries.
The following $N-1$ lines each contain the integers $a$ and $b$ ($0 \leq a,b \leq N-1$), which means that there is an edge between node $a$ and $b$. These edges are guaranteed to form a tree.
Then, the next $Q$ each contain a query. Each query start with the integer $T$.
If $T=0$, the next integer is $u$ ($0 \leq u \leq N-1$), the node to be changed from white to black.
If $T=1$, the next integer is $u$ ($0 \leq u \leq N-1$), the node for which we want to know the distance to the most faraway black node.
Output
For each query where $T=1$, print the largest number of edges on a shortest path from node $u$ to a black node.
Scoring
Your solution will be tested on multiple testcases. To solve the problem, your solution must solve every testcase correctly.
Sample Input 1 Sample Output 1 5 5 0 1 1 2 2 3 2 4 1 0 0 2 1 0 0 3 1 0
0 2 3
-
-
To solve the problems, you can either start a virtual contest or register for regular practice. A virtual contest simulates a participation in the original contest with a duration of 1 day, while regular practice lets you submit solutions without any constraints.
You must log in to register. - Close Node
- Count Nodes
- Faraway Node