Problem Statement
A pair of strings $(S, T)$ consisting of 0 and 1 is called good if and only if all of the following conditions are satisfied.
$S$and$T$contain the same number of0s.$S$and$T$contain the same number of1s.
Particularly, for a good string pair $(S, T)$, $S$ and $T$ have the same length.
For a good string pair $(S, T)$, we define an undirected graph $G(S, T)$ as follows.
- Let
$L$be the length of$S$. Create a graph$g$with vertices$1, 2, \cdots, L$. - Let
$n$be the number of0s in$S$. Let the indices of0s in$S$be$1 \leq a_1 < a_2 < \cdots < a_n \leq L$. Let the indices of0s in$T$be$1 \leq b_1 < b_2 < \cdots < b_n \leq L$. For each$1 \leq i \leq n$, add an edge between vertices$a_i$and$b_i$to$g$. - Let
$m$be the number of1s in$S$. Let the indices of1s in$S$be$1 \leq c_1 < c_2 < \cdots < c_m \leq L$. Let the indices of1s in$T$be$1 \leq d_1 < d_2 < \cdots < d_m \leq L$. For each$1 \leq i \leq m$, add an edge between vertices$c_i$and$d_i$to$g$. - The graph
$g$obtained through the above steps is$G(S, T)$.
You are given an integer sequence $A = (A_1, A_2, \cdots, A_N)$ of length $N$. Find one good string pair $(S, T)$ satisfying all of the following conditions.
- Let
$L$be the length of$S$. It satisfies$N \leq L \leq 10^5$. - For each pair
$1 \leq i, j \leq N$, vertices$i$and$j$belong to the same connected component in$G(S, T)$if and only if$A_i = A_j$.
It can be proved that a solution always exists under the constraints of this problem.
Constraints
$1 \leq N \leq 100$$1 \leq A_i \leq N$- All input values are integers.
Input
The input is given from Standard Input in the following format:
N
A_1 A_2 \cdots A_N
Output
Print a solution in the following format:
L
S
T
Here, $L$ is the length of $S$ and $T$. If multiple solutions exist, any of them will be accepted.
样例
3
1 2 1
4
0011
1100
5
1 2 3 4 5
5
01010
01010
6
1 1 1 1 1 1
6
011111
111110
10
1 2 3 2 4 3 4 4 5 6
21
000101010111100011011
011010000010101111110
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