#D9618. Bichromization
Bichromization
Bichromization
We have a connected undirected graph with N vertices and M edges. Edge i in this graph (1 \leq i \leq M) connects Vertex U_i and Vertex V_i bidirectionally. We are additionally given N integers D_1, D_2, ..., D_N.
Determine whether the conditions below can be satisfied by assigning a color - white or black - to each vertex and an integer weight between 1 and 10^9 (inclusive) to each edge in this graph. If the answer is yes, find one such assignment of colors and integers, too.
- There is at least one vertex assigned white and at least one vertex assigned black.
- For each vertex v (1 \leq v \leq N), the following holds.
- The minimum cost to travel from Vertex v to a vertex whose color assigned is different from that of Vertex v by traversing the edges is equal to D_v.
Here, the cost of traversing the edges is the sum of the weights of the edges traversed.
Constraints
- 2 \leq N \leq 100,000
- 1 \leq M \leq 200,000
- 1 \leq D_i \leq 10^9
- 1 \leq U_i, V_i \leq N
- The given graph is connected and has no self-loops or multiple edges.
- All values in input are integers.
Input
Input is given from Standard Input in the following format:
N M D_1 D_2 ... D_N U_1 V_1 U_2 V_2 \vdots U_M V_M
Output
If there is no assignment satisfying the conditions, print a single line containing -1
.
If such an assignment exists, print one such assignment in the following format:
S C_1 C_2 \vdots C_M
Here,
- the first line should contain the string S of length N. Its i-th character (1 \leq i \leq N) should be
W
if Vertex i is assigned white andB
if it is assigned black. - The (i + 1)-th line (1 \leq i \leq M) should contain the integer weight C_i assigned to Edge i.
Examples
Input
5 5 3 4 3 5 7 1 2 1 3 3 2 4 2 4 5
Output
BWWBB 4 3 1 5 2
Input
5 7 1 2 3 4 5 1 2 1 3 1 4 2 3 2 5 3 5 4 5
Output
-1
Input
4 6 1 1 1 1 1 2 1 3 1 4 2 3 2 4 3 4
Output
BBBW 1 1 1 2 1 1
inputFormat
input are integers.
Input
Input is given from Standard Input in the following format:
N M D_1 D_2 ... D_N U_1 V_1 U_2 V_2 \vdots U_M V_M
outputFormat
Output
If there is no assignment satisfying the conditions, print a single line containing -1
.
If such an assignment exists, print one such assignment in the following format:
S C_1 C_2 \vdots C_M
Here,
- the first line should contain the string S of length N. Its i-th character (1 \leq i \leq N) should be
W
if Vertex i is assigned white andB
if it is assigned black. - The (i + 1)-th line (1 \leq i \leq M) should contain the integer weight C_i assigned to Edge i.
Examples
Input
5 5 3 4 3 5 7 1 2 1 3 3 2 4 2 4 5
Output
BWWBB 4 3 1 5 2
Input
5 7 1 2 3 4 5 1 2 1 3 1 4 2 3 2 5 3 5 4 5
Output
-1
Input
4 6 1 1 1 1 1 2 1 3 1 4 2 3 2 4 3 4
Output
BBBW 1 1 1 2 1 1
样例
5 5
3 4 3 5 7
1 2
1 3
3 2
4 2
4 5
BWWBB
4
3
1
5
2
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