#include <bits/stdc++.h>
#define int long long
#define fastio ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
using namespace std;
const int N = 1e5+5;
int visited[N], arr[N], sz[N], visited2[N], check[N];
vector<int> adj[N];
void dfs(int u){
if(arr[u]==u) check[u] = 1;
sz[u] = 1;
visited[u] = 1;
for(auto v : adj[u]){
if(visited[v]) continue;
dfs(v);
sz[u] += sz[v];
check[u] |= check[v];
}
}
bool dfs2(int u){
if(adj[u].size() >= 2) return true;
visited2[u] = 1;
for(auto v : adj[u]){
if(visited2[v]) continue;
if(dfs2(v)) return true;
}
return false;
}
int idx;
map<string,int> m;
int assign(string x){
if(m.find(x)==m.end()){
m[x] = idx++;
}
return m[x];
}
signed main(){
fastio
int n;
cin >> n;
for(int i = 0;i < n;i++){
string a,b;
cin >> a >> b;
int x = assign(a);
int y = assign(b);
arr[x] = y;
adj[x].push_back(y);
adj[y].push_back(x);
}
if(n%2){
cout << -1 << "\n";
return 0;
}
int ans = 0;
for(int i = 0; i < n; i++){
if(!visited[i]){
dfs(i);
bool tmp = false;
if(check[i]) tmp |= dfs2(i);
if(tmp) ans++;
if(sz[i]!=2){
ans += sz[i]/2;
if(sz[i]%2&&!tmp) ans++;
}
}
}
cout << ans << "\n";
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
1 ms |
2636 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
2636 KB |
Output is correct |
2 |
Correct |
1 ms |
2636 KB |
Output is correct |
3 |
Correct |
1 ms |
2636 KB |
Output is correct |
4 |
Correct |
232 ms |
22160 KB |
Output is correct |
5 |
Correct |
213 ms |
16728 KB |
Output is correct |
6 |
Correct |
214 ms |
22936 KB |
Output is correct |
7 |
Correct |
200 ms |
14396 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
216 ms |
17252 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
1 ms |
2636 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |