URAL 1106 Two Teams

#include<stdio.h>
#include<vector>
#include<string.h>
#include<iostream>
#include<algorithm>
using namespace std;
const int maxn=200;
int color[maxn];
bool vis[maxn];
vector<int>g[maxn];
int ans[maxn];

void dfs(int u){
     vis[u]=true;
     for(int i=0;i<g[u].size();i++){
          int v=g[u][i];
         if(!vis[v]){
              color[v]=3-color[u];
             dfs(v);
         }
     }
}

int main(){
  int n;
    while(scanf("%d",&n)!=EOF){
        memset(vis,false,sizeof(vis));
        memset(color,0,sizeof(color));
        memset(ans,0,sizeof(ans));
        int x;
        for(int i=1;i<=n;i++){
            g[i].clear();
           for(int j=1;;j++){
              scanf("%d",&x);
              if(!x)
               break;
               g[i].push_back(x);
           }
        }
        for(int i=1;i<=n;i++){
           if(!vis[i]){
              color[i]=1;
               dfs(i);
           }
        }
        int sum=0;
        int cnt=-1;
        for(int i=1;i<=n;i++){
           if(color[i]==1){
            sum++;
               ans[++cnt]=i;
           }
        }
        printf("%d\n",sum);
        for(int i=0;i<=cnt;i++){
            printf("%d%c",ans[i],i==cnt?‘\n‘:‘ ‘);
        }
    }
    return 0;
}