#include <bits/stdc++.h>
using namespace std;
#define ll long long
int main() {
ios_base::sync_with_stdio(0), cin.tie(0);
int n, m;
cin >> n >> m;
int v[m][2];
set<int> s;
int col[n + 1]{};
memset(col, -1, sizeof col);
for (int i = 0; i < m; i++) {
cin >> v[i][0] >> v[i][1];
if (!v[i][0]) {
s.insert(i);
} else if (!v[i][1]) {
col[v[i][0]] = i;
}
}
vector<array<int, 2>> ans;
for (int i = 0; i < m; i++) {
if (v[i][0] == v[i][1]) continue;
if (v[i][1]) {
if (col[v[i][1]] != -1) {
ans.push_back({i, col[v[i][1]]});
v[col[v[i][1]]][1] = v[i][1];
v[i][1] = 0;
} else {
int x = *s.begin();
s.erase(s.begin());
ans.push_back({i, x});
v[x][0] = v[i][1];
col[v[i][1]] = x;
v[i][1] = 0;
}
}
if (v[i][0]) {
if (col[v[i][0]] == -1) {
col[v[i][0]] = i;
} else if (col[v[i][0]] != i) {
ans.push_back({i, col[v[i][0]]});
v[col[v[i][0]]][1] = v[i][0];
v[i][0] = 0;
}
}
}
cout << ans.size() << '\n';
for (auto [x, y] : ans) {
cout << x + 1 << ' ' << y + 1 << '\n';
}
return 0;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
344 KB |
Output is correct |
2 |
Correct |
0 ms |
348 KB |
Output is correct |
3 |
Correct |
0 ms |
344 KB |
Output is correct |
4 |
Execution timed out |
2032 ms |
348 KB |
Time limit exceeded |
5 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
43 ms |
8660 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Execution timed out |
2089 ms |
352 KB |
Time limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Execution timed out |
2089 ms |
352 KB |
Time limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Execution timed out |
2036 ms |
348 KB |
Time limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
344 KB |
Output is correct |
2 |
Correct |
0 ms |
348 KB |
Output is correct |
3 |
Correct |
0 ms |
344 KB |
Output is correct |
4 |
Execution timed out |
2032 ms |
348 KB |
Time limit exceeded |
5 |
Halted |
0 ms |
0 KB |
- |