#include <bits/stdc++.h>
using namespace std;
int const N = 2e5 + 1;
vector<int> g[N], h[N];
int main(){
int n, m; cin >> n >> m;
while (m--){
int a, b; cin >> a >> b;
g[a].push_back(b);
h[b].push_back(a);
}
int sign[N] = {};
memset(sign, -1, sizeof sign);
for (int i = 1; i <= n; i++){
if (g[i].size() > 0 && h[i].size() > 0){
for (auto v: g[i]){
if (sign[v] == 1){
cout << -1;
return 0;
}
sign[v] = 0;
}
for (auto v: h[i]){
if (sign[v] == 0){
cout << -1;
return 0;
}
sign[v] = 1;
}
}
}
int cnt = 0;
for (int i = 1; i <= n; i++)
if (sign[i] != -1) cnt++;
cout << cnt << "\n";
for (int i = 1; i <= n; i++)
if (sign[i] != -1) cout << i << " " << sign[i] << "\n";
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
5 ms |
10452 KB |
Output is correct |
2 |
Correct |
5 ms |
10452 KB |
Output is correct |
3 |
Correct |
5 ms |
10452 KB |
Output is correct |
4 |
Correct |
5 ms |
10452 KB |
Output is correct |
5 |
Correct |
5 ms |
10476 KB |
Output is correct |
6 |
Correct |
5 ms |
10452 KB |
Output is correct |
7 |
Correct |
6 ms |
10440 KB |
Output is correct |
8 |
Incorrect |
6 ms |
10452 KB |
Output isn't correct |
9 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
183 ms |
21272 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
5 ms |
10452 KB |
Output is correct |
2 |
Correct |
5 ms |
10452 KB |
Output is correct |
3 |
Correct |
5 ms |
10452 KB |
Output is correct |
4 |
Correct |
5 ms |
10452 KB |
Output is correct |
5 |
Correct |
5 ms |
10476 KB |
Output is correct |
6 |
Correct |
5 ms |
10452 KB |
Output is correct |
7 |
Correct |
6 ms |
10440 KB |
Output is correct |
8 |
Incorrect |
6 ms |
10452 KB |
Output isn't correct |
9 |
Halted |
0 ms |
0 KB |
- |