1 #include <bits/stdc++.h> 2 using namespace std; 3 #define pb push_back 4 #define _for(i,a,b) for(int i = (a);i < (b);i ++) 5 #define _rep(i,a,b) for(int i = (a);i > (b);i --) 6 #define INF 0x3f3f3f3f 7 #define ll long long 8 inline ll read() 9 { 10 ll ans = 0; 11 char ch = getchar(), last = ' '; 12 while(!isdigit(ch)) last = ch, ch = getchar(); 13 while(isdigit(ch)) ans = (ans << 1) + (ans << 3) + ch - '0', ch = getchar(); 14 if(last == '-') ans = -ans; 15 return ans; 16 } 17 inline void write(ll x) 18 { 19 if(x < 0) x = -x, putchar('-'); 20 if(x >= 10) write(x / 10); 21 putchar(x % 10 + '0'); 22 } 23 #define maxn 5003 24 int n,m; 25 vector<int> G[maxn]; 26 vector<int> rG[maxn]; 27 vector<int> vs; 28 vector<int> ans[maxn]; 29 bool used[maxn]; 30 int V,E; 31 int rnt = 0; 32 void add_edge(int from,int to) 33 { 34 G[from].pb(to); 35 rG[to].pb(from); 36 } 37 void dfs(int v) 38 { 39 used[v] = true; 40 _for(i,0,G[v].size()) 41 if(!used[G[v][i]]) 42 dfs(G[v][i]); 43 vs.pb(v); 44 } 45 void rdfs(int v,int k) 46 { 47 used[v] = true; 48 ans[k].pb(v); 49 _for(i,0,rG[v].size()) 50 if(!used[rG[v][i]]) 51 rdfs(rG[v][i],k); 52 } 53 void Kosaraju() 54 { 55 memset(used,0,sizeof(used)); 56 _for(v,1,V+1) 57 if(!used[v]) 58 dfs(v); 59 60 memset(used,0,sizeof(used)); 61 int k = 0; 62 _rep(i,vs.size()-1,-1) 63 if(!used[vs[i]]) 64 { 65 rdfs(vs[i],k); 66 rnt = max(rnt,(int)ans[k].size()); 67 k ++; 68 } 69 } 70 int main() 71 { 72 V = read(),E = read(); 73 _for(i,1,E+1) 74 { 75 int a,b,t; 76 a = read(),b = read(),t = read(); 77 add_edge(a,b); 78 G[a].pb(b); 79 if(2==t) 80 add_edge(b,a); 81 } 82 Kosaraju(); 83 _for(i,0,5000) 84 if(ans[i].size()==rnt) 85 { 86 sort(ans[i].begin(),ans[i].end()); 87 printf("%d ",ans[i].size()); 88 _for(j,0,ans[i].size()) 89 printf("%d ",ans[i][j]); 90 break; 91 } 92 return 0; 93 }