Pagini recente » Diferente pentru problema/becuriacm intre reviziile 4 si 3 | Statistici Negru Mihai (Nobody1) | Rezultatele filtrării | Rezultatele filtrării | Cod sursa (job #1113184)
#include <fstream>
#include <vector>
#include <queue>
#define pb push_back
using namespace std;
ifstream f("maxflow.in");
ofstream g("maxflow.out");
int flow[1002][1002], cap[1002][1002], N, M, x, y, c, source, sink, prec[1002], MaxFlow;
vector < int > G[1002];
queue < int > Q;
bool bfs(int source)
{
Q.push(source);
for (int i=1; i<=N; ++i)
prec[i]=0; prec[source]=source;
vector <int>::iterator it=G[source].begin();
while (Q.size())
{
int nod=Q.back(); Q.pop();
if (nod==sink) continue;
vector <int>::iterator it=G[nod].begin();
for (; it!=G[nod].end(); ++it)
if (!prec[*it] && cap[nod][*it]>flow[nod][*it])
prec[*it]=nod, Q.push(*it);
}
return (prec[sink]>0);
}
void Flow(int source)
{
for (; bfs(source); )
{
vector <int>::iterator it=G[sink].begin();
for(; it!=G[sink].end(); ++it)
if (prec[*it] && cap[*it][sink]>flow[*it][sink])
{
prec[sink]=*it;
int minim=200000000;
for (int x=sink; x!=source; x=prec[x])
if (minim>cap[prec[x]][x]-flow[prec[x]][x])
minim=cap[prec[x]][x]-flow[prec[x]][x];
if (minim>0)
{
MaxFlow+=minim;
for (int x=sink; x!=source; x=prec[x])
flow[prec[x]][x]+=minim, flow[x][prec[x]]-=minim;
}
}
}
}
int main()
{
f>>N>>M; source=1; sink=N;
for (int i=1; i<=N; ++i)
f>>x>>y>>c, G[x].pb(y), G[y].pb(x), cap[x][y]+=c;
Flow(source);
g<<MaxFlow<<'\n';
return 0;
}