Cod sursa(job #2012451)

Utilizator dragomirmanuelDragomir Manuel dragomirmanuel Data 18 august 2017 20:22:21
Problema Componente biconexe Scor 4
Compilator cpp Status done
Runda Arhiva educationala Marime 1.67 kb
#include <iostream>
#include <cstdio>
#include <vector>
#include <set>
#include <bitset>

using namespace std;

const int NodMax = 100005;
const int MuchMax = 200005;
int N, M, cmp_biconexe, timp;
int tov[NodMax], low[NodMax];
bool pa[NodMax];
bitset < NodMax > viz;
set < int > Puncte;
vector < int > G[NodMax];
//tov = time of visit = cand gasesc prima oara nodul x
//low = nivel cel mai mic la care poate ajunge nodul x

void Read()
{
    scanf("%d %d", &N, &M);

    for(int i=1; i<=M; ++i)
    {
        int x, y;
        scanf("%d %d", &x, &y);
        G[x].push_back(y);
        G[y].push_back(x);
    }
}

void DFS(int nod, int dad)
{
    tov[nod] = timp;
    ++timp;
    low[nod] = tov[nod];
    int children = 0;
    viz[nod] = 1;
    vector < int > ::iterator it;

    for(it=G[nod].begin(); it!=G[nod].end(); ++it)
    {
        if( *it == dad)
            continue;

        else
            if(!viz[*it])
        {
            ++children;

            DFS(*it, nod);

            low[nod] = min(low[*it], low[nod]);

            if(dad == 0 && children > 1)
                pa[nod] = true;

            if(tov[nod] <= low[*it])
            {
                  pa[nod] = true;
            }
        }

        else
            low[nod] = min(low[nod], tov[*it]);
    }
}

int main()
{
    freopen("biconex.in", "r", stdin);
    freopen("biconex.out", "w", stdout);
    Read();

    for(int i=1; i<=N; ++i)
    {
        if(!viz[i])
        {
            DFS(i,0);
        }
    }

    int cnt = 0;
    for(int i=1; i<=N; ++i)
        if(pa[i] == true)
            ++cnt;

    cout << cnt + 1;

    return 0;
}