#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ull unsigned long long
#define ld long double
#define fi first
#define se second
queue<int> q;
vector<int> child[200005], ans;
int par[200005];
int main() {
ios_base::sync_with_stdio(false); cin.tie(NULL);
/*
1 2
2 3
3 4
urutan penarikan = 4 -> 3 -> 2 -> 1
urutan pengeboman = 1 -> 2 -> 3 -> 4
3 3
1 2
2 3
1 3
3 -> 2 -> 1
3 -> 1
*/
int n, m;
cin >> n >> m;
for (int i = 0; i < m; i++) {
int u, v;
cin >> u >> v;
child[u].push_back(v);
par[v]++;
}
for (int i = 1; i <= n; i++) if (par[i] == 0) q.push(i);
while (!q.empty()) {
int x = q.front();
q.pop();
ans.push_back(x);
for (auto u : child[x]) {
par[u]--;
if (par[u] == 0) q.push(u);
}
}
for (int i = 1; i <= n; i++) {
if (par[i] != 0) {
cout << -1 << "\n";
return 0;
}
}
cout << (int)ans.size() << "\n";
for (auto x : ans) cout << x << " 0" << "\n";
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
4948 KB |
Output is correct |
2 |
Correct |
2 ms |
4948 KB |
Output is correct |
3 |
Correct |
2 ms |
4948 KB |
Output is correct |
4 |
Correct |
2 ms |
4960 KB |
Output is correct |
5 |
Correct |
2 ms |
4948 KB |
Output is correct |
6 |
Correct |
2 ms |
4948 KB |
Output is correct |
7 |
Correct |
2 ms |
4948 KB |
Output is correct |
8 |
Correct |
2 ms |
4948 KB |
Output is correct |
9 |
Correct |
2 ms |
4948 KB |
Output is correct |
10 |
Correct |
2 ms |
4948 KB |
Output is correct |
11 |
Correct |
2 ms |
4948 KB |
Output is correct |
12 |
Correct |
2 ms |
4948 KB |
Output is correct |
13 |
Correct |
2 ms |
4948 KB |
Output is correct |
14 |
Correct |
2 ms |
5012 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
75 ms |
12772 KB |
Output is correct |
2 |
Correct |
67 ms |
12868 KB |
Output is correct |
3 |
Correct |
31 ms |
9112 KB |
Output is correct |
4 |
Correct |
75 ms |
12836 KB |
Output is correct |
5 |
Correct |
69 ms |
12792 KB |
Output is correct |
6 |
Correct |
69 ms |
12772 KB |
Output is correct |
7 |
Correct |
91 ms |
12868 KB |
Output is correct |
8 |
Correct |
50 ms |
11172 KB |
Output is correct |
9 |
Correct |
83 ms |
12788 KB |
Output is correct |
10 |
Correct |
67 ms |
12860 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
4948 KB |
Output is correct |
2 |
Correct |
2 ms |
4948 KB |
Output is correct |
3 |
Correct |
2 ms |
4948 KB |
Output is correct |
4 |
Correct |
2 ms |
4960 KB |
Output is correct |
5 |
Correct |
2 ms |
4948 KB |
Output is correct |
6 |
Correct |
2 ms |
4948 KB |
Output is correct |
7 |
Correct |
2 ms |
4948 KB |
Output is correct |
8 |
Correct |
2 ms |
4948 KB |
Output is correct |
9 |
Correct |
2 ms |
4948 KB |
Output is correct |
10 |
Correct |
2 ms |
4948 KB |
Output is correct |
11 |
Correct |
2 ms |
4948 KB |
Output is correct |
12 |
Correct |
2 ms |
4948 KB |
Output is correct |
13 |
Correct |
2 ms |
4948 KB |
Output is correct |
14 |
Correct |
2 ms |
5012 KB |
Output is correct |
15 |
Correct |
75 ms |
12772 KB |
Output is correct |
16 |
Correct |
67 ms |
12868 KB |
Output is correct |
17 |
Correct |
31 ms |
9112 KB |
Output is correct |
18 |
Correct |
75 ms |
12836 KB |
Output is correct |
19 |
Correct |
69 ms |
12792 KB |
Output is correct |
20 |
Correct |
69 ms |
12772 KB |
Output is correct |
21 |
Correct |
91 ms |
12868 KB |
Output is correct |
22 |
Correct |
50 ms |
11172 KB |
Output is correct |
23 |
Correct |
83 ms |
12788 KB |
Output is correct |
24 |
Correct |
67 ms |
12860 KB |
Output is correct |
25 |
Correct |
103 ms |
10100 KB |
Output is correct |
26 |
Correct |
69 ms |
11608 KB |
Output is correct |
27 |
Correct |
79 ms |
11776 KB |
Output is correct |
28 |
Correct |
98 ms |
11980 KB |
Output is correct |
29 |
Correct |
80 ms |
11884 KB |
Output is correct |
30 |
Correct |
100 ms |
12008 KB |
Output is correct |
31 |
Correct |
16 ms |
5972 KB |
Output is correct |
32 |
Correct |
71 ms |
11836 KB |
Output is correct |
33 |
Correct |
154 ms |
13700 KB |
Output is correct |
34 |
Correct |
77 ms |
12092 KB |
Output is correct |
35 |
Correct |
120 ms |
13740 KB |
Output is correct |
36 |
Correct |
68 ms |
11892 KB |
Output is correct |
37 |
Correct |
112 ms |
13280 KB |
Output is correct |
38 |
Correct |
97 ms |
12892 KB |
Output is correct |
39 |
Correct |
117 ms |
13600 KB |
Output is correct |
40 |
Correct |
101 ms |
13176 KB |
Output is correct |
41 |
Correct |
155 ms |
13272 KB |
Output is correct |
42 |
Correct |
127 ms |
13816 KB |
Output is correct |
43 |
Correct |
94 ms |
12388 KB |
Output is correct |
44 |
Correct |
127 ms |
13924 KB |
Output is correct |
45 |
Correct |
84 ms |
12120 KB |
Output is correct |
46 |
Correct |
122 ms |
13164 KB |
Output is correct |