Preparando MOJI

Graph

1000ms 262144K

Description:

You are given an undirected graph where each edge has one of two colors: black or red.

Your task is to assign a real number to each node so that:

  • for each black edge the sum of values at its endpoints is $$$1$$$;
  • for each red edge the sum of values at its endpoints is $$$2$$$;
  • the sum of the absolute values of all assigned numbers is the smallest possible.

Otherwise, if it is not possible, report that there is no feasible assignment of the numbers.

Scoring

Subtasks:

  1. (5 points) $$$N \leq 5$$$, $$$M \leq 14$$$
  2. (12 points) $$$N \leq 100$$$
  3. (17 points) $$$N \leq 1000$$$
  4. (24 points) $$$N \leq 10\,000$$$
  5. (42 points) No further constraints

Input:

The first line contains two integers $$$N$$$ ($$$1 \leq N \leq 100\,000$$$) and $$$M$$$ ($$$0 \leq M \leq 200\,000$$$): the number of nodes and the number of edges, respectively. The nodes are numbered by consecutive integers: $$$1, 2, \ldots, N$$$.

The next $$$M$$$ lines describe the edges. Each line contains three integers $$$a$$$, $$$b$$$ and $$$c$$$ denoting that there is an edge between nodes $$$a$$$ and $$$b$$$ ($$$1 \leq a, b \leq N$$$) with color $$$c$$$ ($$$1$$$ denotes black, $$$2$$$ denotes red).

Output:

If there is a solution, the first line should contain the word "YES" and the second line should contain $$$N$$$ space-separated numbers. For each $$$i$$$ ($$$1 \le i \le N$$$), the $$$i$$$-th number should be the number assigned to the node $$$i$$$.

Output should be such that:

  • the sum of the numbers at the endpoints of each edge differs from the precise value by less than $$$10^{-6}$$$;
  • the sum of the absolute values of all assigned numbers differs from the smallest possible by less than $$$10^{-6}$$$.

If there are several valid solutions, output any of them.

If there is no solution, the only line should contain the word "NO".

Sample Input:

4 4
1 2 1
2 3 2
1 3 2
3 4 1

Sample Output:

YES
0.5 0.5 1.5 -0.5

Sample Input:

2 1
1 2 1

Sample Output:

YES
0.3 0.7

Sample Input:

3 2
1 2 2
2 3 2

Sample Output:

YES
0 2 0

Sample Input:

3 4
1 2 2
2 2 1
2 1 1
1 2 2

Sample Output:

NO

Note:

Note that in the second example the solution is not unique.

Informação

Codeforces

Provedor Codeforces

Código CF1387A

Tags

*specialbinary searchdfs and similardpmathternary search

Submetido 0

BOUA! 0

Taxa de BOUA's 0%

Datas 09/05/2023 10:04:58

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