#include <bits/stdc++.h>
using namespace std;
#define int long long
#define ff first
#define ss second
#define all(a) a.begin(), a.end()
const int N = 1e5;
int n;
vector<string> a, b;
vector<string> compr;
map<string,int> compress;
vector<int> g[N+10];
int used[N + 10];
int cnt, loves;
void dfs(int v){
used[v] = 1;
cnt++;
for(int to : g[v]){
if(used[to] == 0){
dfs(to);
}else if(used[to] == 1){
loves++;
}
}
used[v] = 2;
}
main(){
ios::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
cin >> n;
a.resize(n);
b.resize(n);
for(int i = 0;i < n; i++){
cin >> a[i] >> b[i];
compr.push_back(a[i]);
}
sort(all(compr));
int cnt1 = 1;
for(auto x : compr){
compress[x] = cnt1++;
}
for(int i = 0;i < n; i++){
g[compress[a[i]]].push_back(compress[b[i]]);
}
// for(int i = 0;i < n; i++){
// cout << compress[a[i]] << " " << compress[b[i]] << '\n';
// }
if(n%2 == 1){
cout << "-1";
return 0;
}
int ans = 0, self = 0;
for(int i = 1;i <= n; i++){
if(!used[i]){
cnt = 0, loves = 0;
dfs(i);
if(cnt > 2) ans = ans + (cnt / 2);
self = self + (cnt % 2);
}
}
if(self % 2 == 1) assert(false);
ans+= (self * 2);
cout << ans;
return 0;
}
Compilation message
polygon.cpp:32:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
32 | main(){
| ^~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1 ms |
3420 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1 ms |
3420 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
144 ms |
23784 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1 ms |
3420 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
