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Cod sursa(job #383030)
#include<cstdio>
#include<vector>
#include<queue>
#define NMAX 1024
#define min(a,b) ((a)<(b)?(a):(b))
using namespace std;
int C[NMAX][NMAX],F[NMAX][NMAX],H[NMAX],E[NMAX],n;
vector<int> G[NMAX];
queue<int> Q;
inline void push(int x, int y)
{
int v=min(E[x],C[x][y]-F[x][y]);
F[x][y]+=v;
F[y][x]-=v;
E[x]-=v;
if(!E[y] && y!=n)
Q.push(y);
E[y]+=v;
}
inline void lift(int x)
{
int i,v=2*n,y;
for(i=0;i<G[x].size();++i)
{
y=G[x][i];
if(F[x][y]<C[x][y])
v=min(v,H[y]);
}
H[x]=v+1;
}
int main()
{
int Start[NMAX],m,x,y,c,i;
freopen("maxflow.in","r",stdin);
freopen("maxflow.out","w",stdout);
scanf("%d%d",&n,&m);
while(m--)
{
scanf("%d%d%d",&x,&y,&c);
C[x][y]=c;
G[x].push_back(y);
G[y].push_back(x);
}
for(i=1;i<=n;++i)
{
F[1][i]=C[1][i];
F[i][1]=-C[1][i];
E[i]=C[1][i];
}
H[1]=n; H[n]=0;
for(i=2;i<n;++i)
{
H[i]=1;
Start[i]=0;
if(E[i])
Q.push(i);
}
while(!Q.empty())
{
x=Q.front();
for(i=Start[x];i<G[x].size() && E[x];++i)
{
y=G[x][i];
if(H[x]>H[y] && F[x][y]<C[x][y])
push(x,y);
}
if(E[x])
{
lift(x);
Start[x]=0;
}
else
{
Q.pop();
Start[x]=i-1;
}
}
printf("%d\n",E[n]);
return 0;
}