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Cod sursa(job #550752)
#include <queue>
#include <vector>
#include <fstream>
#include <cstdlib>
#define N_MAX 1011
#define oo 1<<20
using namespace std;
int N;
int C[N_MAX][N_MAX];
vector< int > G[N_MAX];
int findPath()
{
int x;
queue< int > Q;
vector< int > f( N+1, -1 );
vector< int >::const_iterator it, iend;
f[1]=-2;
for( Q.push(1); !Q.empty() && -1 == f[N]; )
{
x=Q.front(); Q.pop();
for( it=G[x].begin(), iend=G[x].end(); it < iend; ++it )
if( -1 == f[*it] && C[x][*it] > 0 )
{
f[*it]=x;
Q.push(*it);
}
}
if( -1 == f[N] )
return 0;
int _min=oo;
for( x=N; -2 != f[x]; x=f[x] )
{
_min=( _min <= C[f[x]][x] ? _min : C[f[x]][x] );
}
for( x=N; -2 != f[x]; x=f[x] )
{
C[f[x]][x]-=_min;
C[x][f[x]]+=_min;
}
return _min;
}
int MaxFlow()
{
int s, pathC;
for( s=0, pathC=findPath(); pathC; s+=pathC, pathC=findPath() );
return s;
}
int main( void )
{
int M, x, y;
ifstream in( "maxflow.in" );
for( in>>N>>M; M; --M )
{
in>>x>>y;
in>>C[x][y];
//C[y][x]=C[x][y];
G[x].push_back(y);
G[y].push_back(x);
}
ofstream out( "maxflow.out" );
out<<MaxFlow()<<'\n';
return EXIT_SUCCESS;
}