Cod sursa(job #1072474)

Utilizator DaNutZ2UuUUBB Bora Dan DaNutZ2UuU Data 4 ianuarie 2014 15:13:58
Problema 2SAT Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 2.89 kb
#include<fstream>
#include<vector>
#include<stack>
#include<queue>
#include<cstring>
#include<algorithm>

#define NMAX 200010
#define VEC G[nod][i]
#define PLUS 100002

using namespace std;

ifstream fin("2sat.in");
ofstream fout("2sat.out");

vector<int> G[NMAX],GT[NMAX];
int n,m,CTC[NMAX],nr,degin[NMAX],marked[NMAX],T[NMAX];
bool use[NMAX],sol[NMAX];
stack<int> S;
queue<int> Q;

int complement(int x)
{
    if(x<0)
        return -x;
    return PLUS+x;
}

void read()
{
    fin>>n>>m;
    for(int i=0,x,y,cx,cy;i<m;i++)
    {
        fin>>x>>y;
        cx=complement(x);
        cy=complement(y);
        if(x<0)
            x=PLUS-x;
        if(y<0)
            y=PLUS-y;
        G[cx].push_back(y);
        GT[y].push_back(cx);
        G[cy].push_back(x);
        GT[x].push_back(cy);
    }
}

void PM(vector<int> *G,int nod)
{
    use[nod]=1;
    for(size_t i=0;i<G[nod].size();i++)
        if(!use[VEC])
            PM(G,VEC);
    S.push(nod);
}

void Kosaraju(vector<int> *G,int nod)
{
    use[nod]=1;
    CTC[nod]=nr;
    for(size_t i=0;i<G[nod].size();i++)
        if(!use[VEC])
            Kosaraju(G,VEC);
}

void edges()
{
    for(int nod=1;nod<NMAX;nod++)
    {
        if(CTC[nod])
            T[CTC[nod]]=nod;
        GT[nod].clear();
    }
    for(int nod=1;nod<NMAX;nod++)
        for(size_t i=0;i<G[nod].size();i++)
            if(CTC[nod]!=CTC[VEC])
                GT[CTC[nod]].push_back(CTC[VEC]);
    for(int i=1;i<=nr;i++)
        for(size_t j=0;j<GT[i].size();j++)
            degin[GT[i][j]]++;
}

int main()
{
    read();
    for(int i=1;i<=n;i++)
        if(!use[i])
            PM(G,i);
    for(int i=1+PLUS;i<=n+PLUS;i++)
        if(!use[i])
            PM(G,i);
    memset(use,0,sizeof use);
    for(;!S.empty();S.pop())
        if(!use[S.top()])
        {
            nr++;
            Kosaraju(GT,S.top());
        }
    for(int i=1;i<=n;i++)
        if(CTC[i]==CTC[i+PLUS])
        {
            fout<<"-1\n";
            exit(0);
        }

    edges();
    memset(use,0,sizeof use);
    for(int nod=1;nod<=nr;nod++)
        if(!degin[nod])
            Q.push(nod);
    memset(use,0,sizeof use);
    vector<int> *G=GT;
    for(int nod,cnod,val;!Q.empty();Q.pop())
    {
        nod=Q.front();
        if(use[nod])
            continue;
        use[nod]=1;
        if(!marked[nod])
        {
            val=T[nod];
            if(val<PLUS)
                cnod=CTC[val+PLUS];
            else
                cnod=CTC[val-PLUS];
            marked[nod]=1;
            marked[cnod]=2;
        }
        for(size_t i=0;i<G[nod].size();i++)
        {
            degin[VEC]--;
            if(!degin[VEC])
                Q.push(VEC);
        }
    }
    for(int i=1;i<=n;i++)
        sol[i]=marked[CTC[i]]-1;

    for(int i=1;i<=n;i++)
        fout<<(int)sol[i]<<' ';
    return 0;
}