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Cod sursa(job #757543)
using namespace std;
#include<fstream>
#include<vector>
#include<cstring>
#include<queue>
#define NN 1001
#define pb push_back
ofstream out("maxflow.out");
vector<int>G[NN];
queue<int>Q;
typedef vector<int>::iterator IT;
int fl[NN][NN],cap[NN][NN],n,m,t[NN],ans;
void read();
int BFS();
void solve();
int main()
{
read();
solve();
out<<ans;
return 0;
}
void read()
{
ifstream in("maxflow.in");
in>>n>>m;
for(int x,y,c;m;--m)
{
in>>x>>y>>c;
cap[x][y]=c;
G[x].pb(y);
G[y].pb(x);
}
}
/*
int BFS()
{
memset(uz,0,sizeof(uz));
queue<int>Q;
Q.push(1);
uz[1]=1;
int k;
while(!Q.empty())
{
k=Q.front();
if(k!=n)
for(IT I=G[k].begin();I!=G[k].end();++I)
if(!uz[*I]&&fl[k][*I]<cap[k][*I])
{
uz[*I]=1;
t[*I]=k;
Q.push(*I);
}
Q.pop();
}
return uz[n];
}
void solve()
{
int sol;
while(BFS())
{
for(int i=1;i<n;i++)
if(t[i]&&fl[i][n]<cap[i][n])
{
sol=cap[i][n]-fl[i][n];
for(int j=i;j!=1;j=t[j])
if(cap[t[j]][j]-fl[t[j]][j]<sol)
sol=cap[t[j]][j]-fl[t[j]][j];
if(sol)
{
fl[i][n]+=sol;
fl[n][i]-=sol;
for(int j=i;j!=1;j=t[j])
{
fl[t[j]][j]+=sol;
fl[j][t[j]]-=sol;
}
ans+=sol;
}
}
}
}
*/
int BFS()
{
for(int i=1;i<=n;i++)
t[i]=-1;
t[1]=0;
Q.push(1);
int k;
while(!Q.empty())
{
k=Q.front();
if(k!=n)
for(IT I=G[k].begin();I!=G[k].end();++I)
if(t[*I]==-1&&cap[k][*I]>fl[k][*I])
{
t[*I]=k;
Q.push(*I);
}
Q.pop();
}
return t[n]!=-1;
}
void solve()
{
int sol;
while(BFS())
{
for(IT I=G[n].begin();I!=G[n].end();++I)
if(cap[*I][n]>fl[*I][n])
{
sol=cap[*I][n]-fl[*I][n];
for(int j=*I;j!=1;j=t[j])
if(cap[t[j]][j]-fl[t[j]][j]<sol)
sol=cap[t[j]][j]-fl[t[j]][j];
fl[*I][n]+=sol;
fl[n][*I]-=sol;
for(int j=*I;j!=1;j=t[j])
{
fl[t[j]][j]+=sol;
fl[j][t[j]]-=sol;
}
ans+=sol;
}
}
}