#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
const int MAX = 2e6 + 15;
const int INF = 0x3f3f3f3f;
const int MOD = 1e9 + 7;
#define pb push_back
#define sz(x) (int) x.size()
#define fr first
#define sc second
#define mp make_pair
#define all(x) x.begin(), x.end()
#define dbg(x) cerr << #x << ": " << "[ " << x << " ]\n"
int n, m, ingrau[MAX];
vector<int> adj[MAX];
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> n >> m;
while(m--){
int u, v; cin >> u >> v;
adj[u].pb(v);
ingrau[v]++;
}
vector<int> q;
for(int i = 1; i <= n; i++)
if(ingrau[i] == 0) q.pb(i);
int cur = 0;
while(cur < sz(q)){
int u = q[cur];
for(auto v : adj[u]){
ingrau[v]--;
if(!ingrau[v])
q.pb(v);
}
cur++;
}
if(sz(q) != n){
cout << -1 << '\n';
}else{
cout << sz(q) << '\n';
for(auto x : q)
cout << x << ' ' << 0 << '\n';
}
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
23 ms |
47252 KB |
Output is correct |
2 |
Correct |
24 ms |
47292 KB |
Output is correct |
3 |
Correct |
24 ms |
47252 KB |
Output is correct |
4 |
Correct |
24 ms |
47296 KB |
Output is correct |
5 |
Correct |
24 ms |
47252 KB |
Output is correct |
6 |
Correct |
25 ms |
47300 KB |
Output is correct |
7 |
Correct |
24 ms |
47188 KB |
Output is correct |
8 |
Correct |
28 ms |
47276 KB |
Output is correct |
9 |
Correct |
27 ms |
47188 KB |
Output is correct |
10 |
Correct |
23 ms |
47236 KB |
Output is correct |
11 |
Correct |
24 ms |
47300 KB |
Output is correct |
12 |
Correct |
24 ms |
47188 KB |
Output is correct |
13 |
Correct |
28 ms |
47188 KB |
Output is correct |
14 |
Correct |
25 ms |
47180 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
132 ms |
57320 KB |
Output is correct |
2 |
Correct |
132 ms |
57392 KB |
Output is correct |
3 |
Correct |
82 ms |
52452 KB |
Output is correct |
4 |
Correct |
128 ms |
57320 KB |
Output is correct |
5 |
Correct |
159 ms |
57408 KB |
Output is correct |
6 |
Correct |
152 ms |
57296 KB |
Output is correct |
7 |
Correct |
128 ms |
57312 KB |
Output is correct |
8 |
Correct |
116 ms |
55152 KB |
Output is correct |
9 |
Correct |
138 ms |
57308 KB |
Output is correct |
10 |
Correct |
128 ms |
57304 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
23 ms |
47252 KB |
Output is correct |
2 |
Correct |
24 ms |
47292 KB |
Output is correct |
3 |
Correct |
24 ms |
47252 KB |
Output is correct |
4 |
Correct |
24 ms |
47296 KB |
Output is correct |
5 |
Correct |
24 ms |
47252 KB |
Output is correct |
6 |
Correct |
25 ms |
47300 KB |
Output is correct |
7 |
Correct |
24 ms |
47188 KB |
Output is correct |
8 |
Correct |
28 ms |
47276 KB |
Output is correct |
9 |
Correct |
27 ms |
47188 KB |
Output is correct |
10 |
Correct |
23 ms |
47236 KB |
Output is correct |
11 |
Correct |
24 ms |
47300 KB |
Output is correct |
12 |
Correct |
24 ms |
47188 KB |
Output is correct |
13 |
Correct |
28 ms |
47188 KB |
Output is correct |
14 |
Correct |
25 ms |
47180 KB |
Output is correct |
15 |
Correct |
132 ms |
57320 KB |
Output is correct |
16 |
Correct |
132 ms |
57392 KB |
Output is correct |
17 |
Correct |
82 ms |
52452 KB |
Output is correct |
18 |
Correct |
128 ms |
57320 KB |
Output is correct |
19 |
Correct |
159 ms |
57408 KB |
Output is correct |
20 |
Correct |
152 ms |
57296 KB |
Output is correct |
21 |
Correct |
128 ms |
57312 KB |
Output is correct |
22 |
Correct |
116 ms |
55152 KB |
Output is correct |
23 |
Correct |
138 ms |
57308 KB |
Output is correct |
24 |
Correct |
128 ms |
57304 KB |
Output is correct |
25 |
Correct |
133 ms |
57296 KB |
Output is correct |
26 |
Correct |
151 ms |
57528 KB |
Output is correct |
27 |
Correct |
156 ms |
58616 KB |
Output is correct |
28 |
Correct |
175 ms |
60164 KB |
Output is correct |
29 |
Correct |
128 ms |
56936 KB |
Output is correct |
30 |
Correct |
170 ms |
60016 KB |
Output is correct |
31 |
Correct |
49 ms |
49144 KB |
Output is correct |
32 |
Correct |
144 ms |
57084 KB |
Output is correct |
33 |
Correct |
230 ms |
61612 KB |
Output is correct |
34 |
Correct |
162 ms |
57420 KB |
Output is correct |
35 |
Correct |
243 ms |
61736 KB |
Output is correct |
36 |
Correct |
184 ms |
56888 KB |
Output is correct |
37 |
Correct |
215 ms |
60796 KB |
Output is correct |
38 |
Correct |
181 ms |
59520 KB |
Output is correct |
39 |
Correct |
245 ms |
61520 KB |
Output is correct |
40 |
Correct |
218 ms |
60132 KB |
Output is correct |
41 |
Correct |
212 ms |
60120 KB |
Output is correct |
42 |
Correct |
261 ms |
62216 KB |
Output is correct |
43 |
Correct |
151 ms |
57916 KB |
Output is correct |
44 |
Correct |
248 ms |
62404 KB |
Output is correct |
45 |
Correct |
141 ms |
57376 KB |
Output is correct |
46 |
Correct |
200 ms |
60112 KB |
Output is correct |