Codeforces Round 973 (Div. 2) |
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Finished |
This is the hard version of the problem. In this version, it is not guaranteed that $$$u = v$$$. You can make hacks only if both versions of the problem are solved.
Alice and Bob are playing a fun game on a tree. This game is played on a tree with $$$n$$$ vertices, numbered from $$$1$$$ to $$$n$$$. Recall that a tree with $$$n$$$ vertices is an undirected connected graph with $$$n - 1$$$ edges.
Alice and Bob take turns, with Alice going first. Each player starts at some vertex.
On their turn, a player must move from the current vertex to a neighboring vertex that has not yet been visited by anyone. The first player who cannot make a move loses.
You are given two vertices $$$u$$$ and $$$v$$$. Represent the simple path from vertex $$$u$$$ to $$$v$$$ as an array $$$p_1, p_2, p_3, \ldots, p_m$$$, where $$$p_1 = u$$$, $$$p_m = v$$$, and there is an edge between $$$p_i$$$ and $$$p_{i + 1}$$$ for all $$$i$$$ ($$$1 \le i < m$$$).
You need to determine the winner of the game if Alice starts at vertex $$$1$$$ and Bob starts at vertex $$$p_j$$$ for each $$$j$$$ (where $$$1 \le j \le m$$$).
Each test contains multiple test cases. The first line contains the number of test cases $$$t$$$ ($$$1 \le t \le 10^4$$$). The description of the test cases follows.
The first line of each test case contains a single integer $$$n$$$ ($$$2 \le n \le 2 \cdot 10^5$$$) — the number of vertices in the tree.
Each of the following $$$n - 1$$$ lines contains two integers $$$a$$$ and $$$b$$$ ($$$1 \le a, b \le n$$$), denoting an undirected edge between vertices $$$a$$$ and $$$b$$$. It is guaranteed that these edges form a tree.
The last line of each test case contains two integers $$$u$$$ and $$$v$$$ ($$$2 \le u, v \le n$$$).
It is guaranteed that the path from $$$u$$$ to $$$v$$$ does not pass through vertex $$$1$$$.
It is guaranteed that the sum of $$$n$$$ over all test cases does not exceed $$$2 \cdot 10^5$$$.
For each test case, output $$$m$$$ lines.
In the $$$i$$$-th line, print the winner of the game if Alice starts at vertex $$$1$$$ and Bob starts at vertex $$$p_i$$$. Print "Alice" (without quotes) if Alice wins, or "Bob" (without quotes) otherwise.
331 22 32 361 21 32 42 51 64 541 21 32 42 4
Bob Alice Alice Bob Alice Bob Alice
In the first test case, the path will be ($$$2,3$$$). If Bob starts at vertex $$$2$$$, Alice will not be able to move anywhere on her first turn and will lose.
However, if Bob starts at vertex $$$3$$$, Alice will move to vertex $$$2$$$, and Bob will have no remaining vertices to visit and will lose.
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