题目描述
Problem Statement
You are given a string of length N+1 consisting of A and B: $S = S_0\cdots S_N$.
For each $k=1, \ldots, N,$ solve the following problem.
Alice and Bob will play a game using a set X, which is initially empty. For $t=1,\ldots, k$ in this order, they will do the following action:
- if t is odd, Alice will choose a non-negative integer x and replace X with $X\cup$ {x};
- if t is even, Bob will choose a non-negative integer x and replace X with $X\cup$ {x}.
Let x be $\mathrm{mex}(X)$ after all k actions. If the character S_x is A, Alice wins; if S_x is B, Bob wins. Note that X has at most k elements, so $x = \mathrm{mex}(X) \leq k$ and the character S_x exists.
Print the name of the winner when both players play optimally.
What is $\mathrm{mex}(X)$?
For a finite set X consisting of $non-negative integers, \mathrm{mex}(X)$ is the smallest non-negative integer x such that $x\notin X$.
Input
The input is given from Standard Input in the following format:
N
S
Output
Print N lines. The i-th line should contain the winner's name (Alice or Bob) when both players play optimally in the game with k=i.
Constraints
- $1\leq N\leq 2\times 10^5$
- S is a string of length N+1 consisting of A and B.
Sample Input 1
2
ABB
Sample Output 1
Alice
Bob
Here is a possible progression of the game with k=1.
- Alice chooses x=10.
- $\mathrm{mex}(X)=\mathrm{mex}(\lbrace 10\rbrace) = 0$, and S_0 is A, so Alice wins.
Here is a possible progression of the game with k=2.
- Alice chooses x=2.
- Bob chooses x=0.
- $\mathrm{mex}(X)=\mathrm{mex}(\lbrace 0,2\rbrace) = 1$, and S_1 is B, so Bob wins.
Sample Input 2
4
AAAAA
Sample Output 2
Alice
Alice
Alice
Alice
Sample Input 3
7
BBAABABA
Sample Output 3
Bob
Bob
Alice
Bob
Alice
Bob
Alice
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分