#include <bits/stdc++.h>
#define pb push_back
using namespace std;
const int N = 1e5 + 10;
int n, t, cnt, ans;
bool mark[N];
vector<int> G[N];
unordered_map<string, int> mp;
void dfs(int v) {
mark[v] = true;
cnt++;
int u = G[v][0];
while (!mark[u]) cnt++, mark[u] = true, u = G[u][0];
return;
}
int main() {
ios:: sync_with_stdio(0), cin.tie(0);
cin >> n;
if (n & 1) return cout << "-1\n", 0;
for (int i = 0; i < n; i++) {
string u, v;
cin >> u >> v;
if (mp[u] == 0) mp[u] = ++t;
if (mp[v] == 0) mp[v] = ++t;
G[mp[u]].pb(mp[v]);
}
for (int i = 1; i <= n; i++)
if (!mark[i]) {
dfs(i);
if (cnt ^ 2) ans += (cnt + 1) / 2;
cnt = 0;
}
cout << ans << '\n';
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
1 ms |
2652 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
2648 KB |
Output is correct |
2 |
Correct |
1 ms |
2652 KB |
Output is correct |
3 |
Correct |
1 ms |
2652 KB |
Output is correct |
4 |
Correct |
50 ms |
13396 KB |
Output is correct |
5 |
Correct |
52 ms |
13564 KB |
Output is correct |
6 |
Correct |
52 ms |
13508 KB |
Output is correct |
7 |
Correct |
1 ms |
2648 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
65 ms |
13568 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
1 ms |
2652 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |