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Cod sursa(job #533028)
#include<cstdio>
#include<vector>
#include<queue>
#include<algorithm>
using namespace std;
const int N=1005;
int tot,n,minf,cur,tata[N],nr[N][N],cap[N][N],flux[N][N];
bool viz[N],fd[N],fs[N];
vector<int> rez,L[N];
queue<int> Q;
void read()
{
int m,x,y,c;
freopen("critice.in","r",stdin);
freopen("critice.out","w",stdout);
scanf("%d%d",&n,&m);
for(int i=1;i<=m;i++)
{
scanf("%d%d%d",&x,&y,&c);
nr[x][y]=i;
nr[y][x]=i;
cap[x][y]+=c, L[x].push_back(y);
cap[y][x]+=c, L[y].push_back(x);
}
}
bool drum()
{
Q.push(1);
for(int i=1;i<=n;i++)
viz[i]=false;
viz[1]=true;
while(!Q.empty())
{
int nod=Q.front();
Q.pop();
if(nod==n)
continue;
for(vector<int>::iterator it=L[nod].begin();it!=L[nod].end();it++)
if(!viz[*it] && cap[nod][*it]-flux[nod][*it]>0)
{
Q.push(*it);
viz[*it]=true;
tata[*it]=nod;
}
}
return viz[n];
}
void compute_min(int nod)
{
for(int i=nod;i!=1;i=tata[i])
if(minf>cap[tata[i]][i]-flux[tata[i]][i])
minf=cap[tata[i]][i]-flux[tata[i]][i];
}
void upgrade_flux(int nod)
{
for(int i=nod;i!=1;i=tata[i])
{
flux[tata[i]][i]+=minf;
flux[i][tata[i]]+=minf;
}
}
void dfd(int nod)
{
for(vector<int>::iterator it=L[nod].begin();it!=L[nod].end();it++)
if(!fd[*it] && cap[*it][nod]-flux[*it][nod]>0)
{
fd[*it]=true;
dfd(*it);
}
}
void dfs(int nod)
{
for(vector<int>::iterator it=L[nod].begin();it!=L[nod].end();it++)
if(!fs[*it] && cap[nod][*it]-flux[nod][*it]>0)
{
fs[*it]=true;
dfs(*it);
}
}
void solve()
{
while(drum())
{
for(vector<int>::iterator it=L[n].begin();it!=L[n].end();it++)
if(viz[*it])
{
minf=cap[*it][n]-flux[*it][n];
compute_min(*it);
upgrade_flux(*it);
tot+=minf;
flux[*it][n]+=minf;
flux[n][*it]+=minf;
}
}
fs[1]=true;
dfs(1);
fd[n]=true;
dfd(n);
}
void init()
{
for(int i=1;i<=n;i++)
for(vector<int>::iterator it=L[i].begin();it!=L[i].end();it++)
if(cap[i][*it]-flux[i][*it]==0 && fs[i] && fd[*it])
rez.push_back(nr[i][*it]);
sort(rez.begin(),rez.end());
rez.resize(unique(rez.begin(),rez.end())-rez.begin());
}
void afis()
{
printf("%d\n",rez.size());
for(vector<int>::iterator it=rez.begin();it!=rez.end();it++)
printf("%d\n",*it);
}
int main()
{
read();
solve();
init();
afis();
return 0;
}