#include<bits/stdc++.h>
#include<chrono>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef long double ld;
typedef string str;
typedef bool bl;
typedef vector<ll> vii;
typedef pair<ll,ll> pii;
typedef vector<pii> vpi;
#define ordered_set tree<pii,null_type,less<pii>,rb_tree_tag,tree_order_statistics_node_update>
#define fast ios_base::sync_with_stdio(0);cin.tie();
#define test ll qqqqq;cin>>qqqqq;while(qqqqq--)
#define test1 ll qqqqq=1;while(qqqqq--)
#define F first
#define S second
#define forn(i,n) for(int i=0;i<n;i++)
#define forx(i,j,n) for(int i=j;i<n;i++)
#define pb push_back
#define eb emplace_back
#define pob pop_back
#define all(v) v.begin(),v.end()
#define lb lower_bound
#define ub upper_bound
#define pow powww
#define prtll(x) printf("%lld",x)
#define prtld(x) printf("%Lf",x)
#define prtst(x) printf("%s",x)
#define prtch(x) printf("%c",x)
#define measure chrono::high_resolution_clock::now()
#define duration chrono::duration_cast<chrono::milliseconds>(end-start)
#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
const ll dx[]{1,0,-1,0,1,-1,1,-1};
const ll dy[]{0,-1,0,1,1,-1,-1,1};
const ll inf=1e18;
const ll mod=1e9+7;
const ll LM=1e8+1;
const ll M=5e5+10;
const ll MM=4002;
const ll MMM=501;
const ld pi=acos(-1);
//const ll mod=998244353;
ll pow(ll r,ll to,ll m=mod){
ll res=1;
r%=m;
while(to){
if((to&1)){
res*=r,res%=m;
}
r*=r,r%=m;
to=(to>>1);
}
return res;
}
ll n,m,mp[M];
vii v[M];
bl vis[M];
ll col[M];
ll inv(ll x){
if(x==1)
return 2;
else
return 1;
}
int main(){
fast
//freopen("gen.txt","r",stdin);
auto start=measure;
test1{
cin>>n>>m;
forn(i,m){
ll x,y;
cin>>x>>y;
v[y].pb(x);
mp[x]=1;
}
queue<ll>q;
forx(i,1,n+1){
if(!mp[i])
q.push(i),col[i]=1;
}
while(!q.empty()){
ll r=q.front();
q.pop();
for(auto it:v[r]){
if(vis[it]){
if(col[it]==col[r]){
cout<<-1<<'\n';
return 0;
}
continue;
}
vis[it]=1;
col[it]=inv(col[r]);
q.push(it);
}
}
vii ans;
forx(i,1,n+1){
if(col[i]==1)
ans.pb(i);
}
cout<<ans.size()<<'\n';
for(auto it:ans)
cout<<it<<' ';
}
auto end=measure;
auto dur=duration;
//cout<<fixed<<dur.count()<<'\n';
return 0;
}
/*
*/
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
172 ms |
38488 KB |
Output is correct |
2 |
Correct |
141 ms |
38384 KB |
Output is correct |
3 |
Correct |
7 ms |
12032 KB |
Output is correct |
4 |
Correct |
52 ms |
26700 KB |
Output is correct |
5 |
Correct |
103 ms |
33844 KB |
Output is correct |
6 |
Correct |
132 ms |
40644 KB |
Output is correct |
7 |
Correct |
89 ms |
28196 KB |
Output is correct |
8 |
Correct |
161 ms |
37952 KB |
Output is correct |
9 |
Correct |
274 ms |
33660 KB |
Output is correct |
10 |
Incorrect |
131 ms |
35452 KB |
Output isn't correct |
11 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
142 ms |
38564 KB |
Output is correct |
2 |
Correct |
128 ms |
41168 KB |
Output is correct |
3 |
Correct |
83 ms |
27444 KB |
Output is correct |
4 |
Incorrect |
202 ms |
32212 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
11 ms |
12376 KB |
Output is correct |
2 |
Correct |
9 ms |
12372 KB |
Output is correct |
3 |
Correct |
10 ms |
12252 KB |
Output is correct |
4 |
Incorrect |
9 ms |
12244 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
172 ms |
38488 KB |
Output is correct |
2 |
Correct |
141 ms |
38384 KB |
Output is correct |
3 |
Correct |
7 ms |
12032 KB |
Output is correct |
4 |
Correct |
52 ms |
26700 KB |
Output is correct |
5 |
Correct |
103 ms |
33844 KB |
Output is correct |
6 |
Correct |
132 ms |
40644 KB |
Output is correct |
7 |
Correct |
89 ms |
28196 KB |
Output is correct |
8 |
Correct |
161 ms |
37952 KB |
Output is correct |
9 |
Correct |
274 ms |
33660 KB |
Output is correct |
10 |
Incorrect |
131 ms |
35452 KB |
Output isn't correct |
11 |
Halted |
0 ms |
0 KB |
- |