poj3648 wedding 2-SAT

#include<iostream>

#include<cstdio>

#include<algorithm>

#include<cstring>

using namespace std;

int n,m;

#include<vector>

#define N 8200

int e[N],v[N],ne[N];

int nn;

void add(int x,int y){

   ne[++nn]=e[x],e[x]=nn,v[nn]=y;

}

int e2[N],nn2,v2[N],ne2[N];

void add2(int x,int y){

    ne2[++nn2]=e2[x],e2[x]=nn2,v2[nn2]=y;

}

int stn,st[N];

int been[N];

int low[N],dfn[N];

int in[N];

int ru[N],tot,bn;

vector<int> jj[N];

int col[N];

void cl(){

   memset(col,0,sizeof(col));

   memset(been,0,sizeof(been));

   memset(low,0,sizeof(low));

   memset(dfn,0,sizeof(dfn));

   memset(e,0,sizeof(e));

   memset(e2,0,sizeof(e2));

   memset(ru,0,sizeof(ru));

   nn=0,nn2=0;

   bn=0;

   tot=0;

}

int qu[N],he,bo;

void dfs(int x){

    low[x]=dfn[x]=++tot;

    st[++stn]=x;

    been[x]=1;

    for(int i=e[x];i;i=ne[i]){

        if(!dfn[v[i]]){

           dfs(v[i]);

           low[x]=min(low[x],low[v[i]]);

        }else if(been[v[i]])low[x]=min(low[x],dfn[v[i]]);

    }

    if(dfn[x]==low[x]){

       bn++;

       do{

            in[st[stn]]=bn;

            been[st[stn]]=0;

        }while(st[stn--]!=x);

    }

}

int main(){

    while(scanf("%d%d",&n,&m),n){

        cl();

        for(int i=1;i<=m;i++){

           int a,b;

           char c,d;

           scanf("%d",&a);

           scanf("%c",&c);

           scanf("%d",&b);

           scanf("%c",&d);

           a++,b++;

            if(c==‘h‘){

               if(d==‘h‘)add(a,b+n),add(b,a+n);

               else add(a,b),add(b+n,a+n);

            }

            if(c==‘w‘){

               if(d==‘h‘)add(a+n,b+n),add(b,a);

                else add(a+n,b),add(b+n,a);

            }

        }

        add(1+n,1);

        for(int i=1;i<=n*2;i++)if(!dfn[i])dfs(i);
for(int i=1;i<=n;i++)if(in[i]==in[i+n]){

           printf("bad luck\n");

           goto loop;

        }

        for(int i=1;i<=n*2;i++){

           for(int j=e[i];j;j=ne[j])if(in[i]!=in[v[j]]){

                add2(in[v[j]],in[i]);

                ru[in[i]]++;

            }

        }

        for(int i=1;i<=bn;i++)jj[i].clear();

        for(int i=1;i<=n;i++){

            jj[in[i]].push_back(in[i+n]);

            jj[in[i+n]].push_back(in[i]);

        }

        bo=1;

        he=0;

        for(int i=1;i<=bn;i++){

            if(!ru[i])qu[++he]=i;

        }

        while(he>=bo){

           int x=qu[bo++];
if(col[x])continue;

           for(int j=0;j<jj[x].size();j++){

                col[jj[x][j]]=1;

            }

            for(int i=e2[x];i;i=ne2[i]){

                ru[v2[i]]--;

                if(!ru[v2[i]])qu[++he]=v2[i];

            }
}

        for(int i=2;i<=n;i++)if(col[in[i]]){

            printf("%dh ",i-1);

        }else{

            printf("%dw ",i-1);

        }

        printf("\n");

        loop:;

    }

}

poj3648 wedding 2-SAT