201433: [AtCoder]ARC143 D - Bridges
Description
Score : $700$ points
Problem Statement
We have two sequences $A_1,\ldots, A_M$ and $B_1,\ldots,B_M$ consisting of intgers between $1$ and $N$ (inclusive).
For a string of length $M$ consisting of 0
and 1
, consider the following undirected graph with $2N$ vertices and $(M+N)$ edges corresponding to that string.
- If the $i$-th character of the string is
0
, the $i$-th edge connects Vertex $A_i$ and Vertex $(B_i+N)$. - If the $i$-th character of the string is
1
, the $i$-th edge connects Vertex $B_i$ and Vertex $(A_i+N)$. - The $(j+M)$-th edge connects Vertex $j$ and Vertex $(j+N)$.
Here, $i$ and $j$ are integers such that $1 \leq i \leq M$ and $1 \leq j \leq N$, and the vertices are numbered $1$ to $2N$.
Find one string of length $M$ consisting of 0
and 1
such that the corresponding undirected graph has the minimum number of bridges.
Notes on bridges
A bridge is an edge of a graph whose removal increases the number of connected components.Constraints
- $1 \leq N \leq 2 \times 10^5$
- $1 \leq M \leq 2 \times 10^5$
- $1 \leq A_i, B_i \leq N$
Input
Input is given from Standard Input in the following format:
$N$ $M$ $A_1$ $A_2$ $\cdots$ $A_M$ $B_1$ $B_2$ $\cdots$ $B_M$
Output
Print one string that satisfies the requirement. If there are multiple such strings, you may print any of them.
Sample Input 1
2 2 1 1 2 2
Sample Output 1
01
The graph corresponding to 01
has no bridges.
In the graph corresponding to 00
, the edge connecting Vertex $1$ and Vertex $3$ and the edge connecting Vertex $2$ and Vertex $4$ are bridges, so 00
does not satisfy the requirement.
Sample Input 2
6 7 1 1 2 3 4 4 5 2 3 3 4 5 6 6
Sample Output 2
0100010