Cod sursa(job #2601034)

Utilizator dorupopDoru Pop dorupop Data 13 aprilie 2020 16:48:11
Problema Critice Scor 100
Compilator cpp-64 Status done
Runda Arhiva de probleme Marime 2.46 kb
#include <fstream>
#include <cstdlib>
#include <algorithm>
#include <vector>
#include <climits>
#include <queue>
using namespace std;
ifstream fin("critice.in");
ofstream fout("critice.out");
vector <int> g[1001];
vector <int> sol;
queue <int> q;
int f[1001][1001],c[1001][1001];
int tata[1001];
bool viz[1001],viz1[1001];
int n,m;
struct muchii
{
    int x,y;
}v[10001];
bool bfs(int start)
{
    q.empty();
    for(int i=1;i<=n;i++)
        tata[i]=viz[i]=0;
    viz[start]=1;
    q.push(start);
    while(!q.empty())
    {
        int nod=q.front();
        q.pop();
        for(int i=0;i<g[nod].size();i++)
        {
            int nou=g[nod][i];
            if(viz[nou]==0&&c[nod][nou]>f[nod][nou])
            {
                viz[nou]=1;
                q.push(nou);
                tata[nou]=nod;
            }
        }
    }
    return viz[n];
}
void bfs1()
{
    viz1[n]=1;
    q.empty();
    q.push(n);
    while(!q.empty())
    {
        int nod=q.front();
        q.pop();
        for(int i=0;i<g[nod].size();i++)
        {
            int nou=g[nod][i];
            if(f[nou][nod]<c[nou][nod]&&viz1[nou]==0)
            {
                viz1[nou]=1;
                q.push(nou);
            }
        }
    }
}
int minim(int nod)
{
    int Min=c[nod][n]-f[nod][n];
    while(nod!=1)
    {
        int nou=tata[nod];
        Min=min(Min,c[nou][nod]-f[nou][nod]);
        nod=nou;
    }
    return Min;
}
void add(int val, int nod)
{
    f[nod][n]+=val;
    f[n][nod]-=val;
    while(nod!=1)
    {
        int nou=tata[nod];
        f[nou][nod]+=val;
        f[nod][nou]-=val;
        nod=nou;
    }
}
void flux()
{
    while(bfs(1))
        for(int i=0;i<g[n].size();i++)
        {
            int nod=g[n][i];
            if(c[nod][n]<=f[nod][n]||viz[nod]==0)
                continue;

            int qmin=minim(nod);
            add(qmin,nod);
        }
}

int main()
{
    fin>>n>>m;
    for(int i=1;i<=m;i++)
    {
        int x,y,ct;
        fin>>x>>y>>ct;
        v[i]={x,y};
        g[x].push_back(y);
        g[y].push_back(x);
        c[x][y]=c[y][x]=ct;
    }
    flux();
    bfs1();
    for(int i=1;i<=m;i++)
    {
        int x=v[i].x;
        int y=v[i].y;
        if(viz[x]==1&&viz1[y]==1||viz1[x]==1&&viz[y]==1)
            sol.push_back(i);
    }
    fout<<sol.size()<<'\n';
    for(int i=0;i<sol.size();i++)
        fout<<sol[i]<<'\n';
    return 0;
}