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A15923 | Removing Graph

时间限制1s
内存限制256MB
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题目描述

Alice and Bob are playing a game on a graph. They have an undirected graph without self-loops and multiple edges. All vertices of the graph have degree equal to $2$ . The graph may consist of several components. Note that if such graph has $n$ vertices, it will have exactly $n$ edges.

Alice and Bob take turn. Alice goes first. In each turn, the player can choose $k$ ( $l \le k \le r$ ; $l < r$ ) vertices that form a connected subgraph and erase these vertices from the graph, including all incident edges.

The player who can't make a step loses.

For example, suppose they are playing on the given graph with given $l = 2$ and $r = 3$ :

![](/uploads/acgo/image/2a02ed28fe91a03c_4c0de9b59269.jpeg)A valid vertex set for Alice to choose at the first move is one of the following:

- $\{1, 2\}$
- $\{1, 3\}$
- $\{2, 3\}$
- $\{4, 5\}$
- $\{4, 6\}$
- $\{5, 6\}$
- $\{1, 2, 3\}$
- $\{4, 5, 6\}$

Suppose, Alice chooses subgraph $\{4, 6\}$ .Then a valid vertex set for Bob to choose at the first move is one of the following:

- $\{1, 2\}$
- $\{1, 3\}$
- $\{2, 3\}$
- $\{1, 2, 3\}$

Suppose, Bob chooses subgraph $\{1, 2, 3\}$ .Alice can't make a move, so she loses.

You are given a graph of size $n$ and integers $l$ and $r$ . Who will win if both Alice and Bob play optimally.

输入格式

The first line contains three integers $n$ , $l$ and $r$ ( $3 \le n \le 2 \cdot 10^5$ ; $1 \le l < r \le n$ ) — the number of vertices in the graph, and the constraints on the number of vertices Alice or Bob can choose in one move.

Next $n$ lines contains edges of the graph: one edge per line. The $i$ -th line contains two integers $u_i$ and $v_i$ ( $1 \le u_i, v_i \le n$ ; $u_i \neq v_i$ ) — description of the $i$ -th edge.

It's guaranteed that the degree of each vertex of the given graph is equal to $2$ .

输出格式

Print Alice (case-insensitive) if Alice wins, or Bob otherwise.

输入输出样例

输入 #1
6 2 3
1 2
2 3
3 1
4 5
5 6
6 4
输出 #1
Bob
输入 #2
6 1 2
1 2
2 3
3 1
4 5
5 6
6 4
输出 #2
Bob
输入 #3
12 1 3
1 2
2 3
3 1
4 5
5 6
6 7
7 4
8 9
9 10
10 11
11 12
12 8
输出 #3
Alice
C++ 编辑器
输入
输出