10480 - Sabotage

[sharklu2000]

I want to use search but I think it's inefficient. Is there any efficient and
easy algorithm? Any hint is aprreciated.

[Larry]

Max-flow min-cut, look it up..

[sharklu2000]

I know Max-flow, but it only calculates the minimum number of edges
to cut. How can I know the minimum cost?

[Kevin]

Does anyone have any test cases for this problem? It seems like it's just straight forward min-cut.

Code: Select all

Snip

Thanks!

[Kevin]

Here's some test cases that I came up with. The solutions to these are not necessarily unique.

Input:

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5 8
1 4 30
1 3 70
5 3 20
4 3 5
4 5 15
5 2 10
3 2 25
2 4 50

5 8
1 4 30
1 3 70
5 3 20
4 3 5
4 5 15
5 2 10
3 2 25
2 4 50

7 8
1 3 1
1 4 2
1 5 2
3 6 2
4 6 1
5 7 1
6 2 2
7 2 2

4 5
1 3 1
1 4 2
3 4 1
3 2 2
4 2 1

4 5
1 3 1
1 4 3
3 4 1
3 2 2
4 2 1

4 5
1 3 1
1 4 4
3 4 1
3 2 2
4 2 2

7 8
1 3 10
3 4 3
3 5 3
3 6 3
4 2 4
5 7 4
6 7 4
7 2 4

5 4
1 3 10
1 2 20
1 5 30
1 4 40

0 0

Output:

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1 4
3 2
3 4
3 5

1 4
3 2
3 4
3 5

1 3
4 6
5 7

1 3
1 4

1 3
4 2
4 3

1 3
4 2
4 3

3 4
7 2

1 2

[DD]

I know Max-flow, but it only calculates the minimum number of edges
to cut. How can I know the minimum cost?

Use the cost as the capacity for each edge.

[Imti]

Data set for this problem is weak,I think.As,The Graph is undirected.
Output for following should be:

Code: Select all

7 7
1 4 2
4 5 5
5 2 2
1 7 3
7 5 3
4 6 3
6 2 3
0 0

My latest accepted approach Outputs:

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1 4
1 7

But my another accepted(Not supposed to get accepted ) outputs:

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1 4
5 4
5 2

which is definitely wrong.

[forthright48]

This is the second problem I solved after learning flow algorithm. After figuring out that max flow is equivalent to min cut, the difficult part was finding a way to print the cuts. Read few books but it didn't help. Took me 3 days to find the following link. Hope it helps some one.

http://stackoverflow.com/questions/4482 ... -algorithm

[zuneera]

Hmmm~~, how about the stategy above?