40分求助，判断"h23"这种两位数问题还是错了！

rt,

#include<bits/stdc++.h>
#define ll long long
using namespace std;
ll t,n,m,dfn[2010],low[2010],cnt,num,tjvis[210];
ll h[2010];
vector<ll> g[2010];
stack<ll> st;
bool ist[2010];
void tarjan(ll u){
    //printf("tarjan %lld %lld start\n",u,fa);
    dfn[u] = low[u] = ++cnt;
    st.push(u);
    ist[u]=1;
    for(ll i=0;i<g[u].size();i++){
        ll v = g[u][i];
        if(!dfn[v])tarjan(v),low[u] = min(low[u],low[v]);
        else if(ist[i])low[u] = min(low[u],dfn[v]);
    }
    //printf("low[%lld] = %lld,dfn[%lld] = %lld\n",u,low[u],u,dfn[u]);
    if(low[u] == dfn[u]){
        num++;
        ll i;
        while(1){
            i = st.top();
            //h[num].push_back(i);
            h[i] = num;
            //printf("h[%lld].push_back(%lld)\n",num,i);
            ist[i] = 0;
            st.pop();
            if(i == u)break;
        }
    }
    //printf("tarjan %lld %lld over\n",u,fa);
}
int main(){
    cin >> t;
    while(t--){
        cin >> n >> m;
        for(ll i=1;i<=2009;i++)g[i].clear();
        memset(h,0,sizeof(h));
        memset(dfn,0,sizeof(dfn));
        memset(low,0,sizeof(low));
        memset(ist,0,sizeof(ist));
        cnt=0;num=0;
        while(!st.empty())st.pop();
        for(ll s1,s2,i=1;i<=m;i++){
            char c1,c2;bool f1,f2;
            c1=0;
            while(c1 != 'm' && c1 != 'h')c1 = getchar();
            //scanf("%c%lld %c%lld",c1,s1,c2,s2);
            cin >> s1;
            getchar();c2 = getchar();
            cin >> s2;
            printf("c1 = %c,s1 = %lld,c2 = %c,s2 = %lld\n",c1,s1,c2,s2);
            if(c1 == 'm')f1 = 0;
            else f1 = 1;
            if(c2 == 'm')f2 = 0;
            else f2 = 1;
            g[!f1 * n + s1].push_back(f2 * n + s2);
            g[!f2 * n + s2].push_back(f1 * n + s1);
            printf("join %lld to %lld,%lld to %lld\n",!f1*n+s1,f2*n+s2,!f2 * n + s2,f1 * n + s1);
        }
        for(ll i=1;i<=n*2;i++){
            if(!dfn[i])tarjan(i);
        }
        bool f=0;
        for(ll i=1;i<=n;i++){
            if(h[i] == h[i+n])f=1;
        }
        if(f == 1){
            cout << "BAD\n";
        }
        else cout << "GOOD\n";
    }
}