#include<bits/stdc++.h> #define ll long long #define all(a) (a).begin(),(a).end() #define bg begin() #define en end() #define pb push_back #define _p pop_front #define p_ pop_back #define fi first #define se second #define ass assign #define sz size() #define el '\n' #define pii pair<int,int> #define pll pair<ll,ll> using namespace std; const int Mod=1e9+7; const int lmt=1e6+7; void file(){ #define TASK "CROSS" if(fopen(TASK".INP","r")) freopen(TASK".INP","r",stdin), freopen(TASK".OUT","w",stdout); } int n,m; vector<vector<int>>adj; vector<bool>vst; vector<int>dist,d; void init(){ cin>>n>>m; vst.ass(n+1,0); adj.ass(n+1,{}); dist.ass(n+1,0); d.ass(n+1,0); for(int i=1;i<=m;i++){ int u,v; cin>>u>>v; adj[u].pb(v); adj[v].pb(u); } for(int i=1;i<=n;i++) cin>>d[i]; } void bfs(int cur){ fill(all(vst),0); fill(all(dist),INT_MAX); dist[cur]=0; queue<int>q; q.push(cur); while(q.sz){ int u=q.front(); q.pop(); vst[u]=1; for(int v:adj[u]){ if(vst[v]) continue; q.push(v); dist[v]=min(dist[v],dist[u]+1); } } } void solve(){ vector<int>res; for(int i=1;i<=n;i++){ bfs(i); bool check=1; for(int j=1;j<=n;j++){ if(d[j]==-1) continue; if(dist[j]!=d[j]){ check=0; break; } } if(check) res.pb(i); } sort(all(res)); cout<<res.sz<<el; for(int x:res) cout<<x<<' '; } int main(){ ios_base::sync_with_stdio(0); cin.tie(0),cout.tie(0); file(); init(); solve(); } /* */

Main.cpp: In function 'void file()':
Main.cpp:24:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   24 |         freopen(TASK".INP","r",stdin),
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
Main.cpp:25:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   25 |         freopen(TASK".OUT","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~