FASTFLOW - Fast Maximum Flow

Given a graph with N (2 ≤ N ≤ 5,000) vertices numbered 1 to N and M (1 ≤ M ≤ 30,000) undirected, weighted edges, compute the maximum flow / minimum cut from vertex 1 to vertex N.

Input

The first line contains the two integers N and M. The next M lines each contain three integers A, B, and C, denoting that there is an edge of capacity C (1 ≤ C ≤ 109) between nodes A and B (1 ≤ A, B ≤ N). Note that it is possible for there to be duplicate edges, as well as an edge from a node to itself.

Output

Print a single integer (which may not fit into a 32-bit integer) denoting the maximum flow / minimum cut between 1 and N.

Example

Input:
4 6
1 2 3
2 3 4
3 1 2
2 2 5
3 4 3
4 3 3

Output:
5

Viewing the problem as max-flow, we may send 3 units of flow through the path 1 - 2 - 3 - 4 and 2 units of flow through the path 1 - 3 - 4. Viewing the problem as min-cut, we may cut the first and third edges. Either way the total is 5.

Note: see also http://www.spoj.com/problems/MATCHING/.


Added by:Neal Wu
Date:2009-03-25
Time limit:2s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: ERL JS-RHINO

hide comments
2016-01-10 05:57:59
Dinic 's time is O(N^2*M), but N is 5000 and M is 30000. Will it get a pass ??? I'm not sure.
2015-07-30 17:04:32 Dario Pavlovic
yup, a well written dinic works.
2015-07-14 01:01:59
dinic's algorithm works ;)

Last edit: 2015-07-14 01:09:48
2015-05-28 16:35:09 (Tjandra Satria Gunawan)(曾毅昆)
very fun! among 931 accepted users (for now), only 10 of them using pure C language ;-)
2015-01-22 09:17:23 dened
My solution using highest-label push-relabel algorithm was accepted even without any heuristics. But I had to implement an efficient data structure for the sparse graph.
2014-12-23 13:41:26 Reza
Dinic --> Accepted. trust me :-"
2014-11-30 20:54:09 Anuj Arora
Very hard problem.......too many TLE......phewww
2014-08-12 16:39:25 Luis Manuel D�az Bar�n
Edmonds-Karp TLE on test 11. It should be allowed to pass

Last edit: 2014-08-25 17:34:51
2014-08-07 20:56:07 rahul kumar
can anybody tell me why im getting WA on 12th test
2014-07-15 13:37:33 Anmol Pandey
Edmond-Karps algo gives TLE

Last edit: 2014-07-15 13:38:40
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