MATCHING  Fast Maximum Matching
FJ has N (1 ≤ N ≤ 50,000) cows and M (1 ≤ M ≤ 50,000) bulls. Given a list of P (1 ≤ P ≤ 150,000) potential matches between a cow and a bull, compute the greatest number of pairs that can be matched. Of course, a cow can be matched to at most one bull, and vice versa.
Input
The first line contains three integers, N, M, and P. Each of the next P lines contains two integers A (1 ≤ A ≤ N) and B (1 ≤ B ≤ M), denoting that cow A can be matched with bull B.
Output
Print a single integer that is the maximum number of pairs that can be obtained.
Example
Input: 5 4 6 5 2 1 2 4 3 3 1 2 2 4 4 Output: 3
Cow 1 can be matched to bull 2, cow 3 to bull 1, and cow 4 to bull 3.
Note: see also http://www.spoj.com/problems/FASTFLOW/.
hide comments
treenipples:
20210523 12:34:10
Kuhn's BPM passes if you shuffle the graph Last edit: 20210523 20:02:16 

nemesys:
20201009 04:59:49
Got TLE with Dinic 

emej:
20200315 17:24:01
Edmond karp barely passes 

threat_:
20191016 02:42:51
Edmond Karp passes 

msh2481:
20181002 07:04:04
Fast Kuhn get AC) 

joqsan_77:
20180822 16:54:52
A wellwritten Dinic's algorithm passes. 

vincecao:
20171205 12:50:13
always tle made me try every possible way to reduce the time cost, however it resulted in the bug in HK causing the dead loop... 

simp:
20171121 04:06:56
Kuhn will not pass, you should use algorithm HopcroftKarp. 

br4in1:
20171120 16:12:24
simple dp 

Luis Manuel Díaz Barón:
20170529 17:34:09
Kuhn > TLE .... WHY???? Has anyone got AC using Kuhn ?? 
Added by:  Neal Wu 
Date:  20090412 
Time limit:  0.400s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All except: ERL JSRHINO 