/* Author : Mychecksdead */
#include<bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef long double ld;
#define MOD (1000000000+7)
#define MOD1 (998244353)
#define PI 3.1415926535
#define pb push_back
#define setp() cout << setprecision(15)
#define all(x) x.begin(), x.end()
#define debug(x) cerr << #x << " is " << x << '\n';
const int N = 1e6+100, M = 1e5+10, F = 2147483646, K = 20;
int n, to[N], res = 0;
string x, y;
vector<int> in(N);
map<string, int> s;
vector<int> g[N];
vector<bool> vis(N);
void dfs(int v, int d){
vis[v] = 1;
for(int u: g[v]){
if(vis[u]){
if(d > 2) res += (d+1)/2;
else if(d == 1) res++;
}else dfs(u, d + 1);
}
}
void solve(){
cin >> n;
int c = 1;
for(int i = 0; i < n; ++i){
cin >> x >> y;
if(s[x] == 0) s[x] = c++;
if(s[y] == 0) s[y] = c++;
int a = s[x] - 1, b = s[y] - 1;
to[a] = b;
g[a].pb(b);
assert(g[a].size()>1);
}
if(n&1){
cout << -1;
return;
}
if(n <= 20){
int ans = n;
for(int mask = 0; mask < (1<<n); ++mask){
bool ok = 1;
vector<int> v;
for(int j = 0; j < n; ++j){
if(!((1<<j)&mask)){
v.pb(to[j]);
if(to[j] == j) ok = 0;
else if(!(to[to[j]] == j || ((1<<to[j])&mask))) ok = 0;
}
}
sort(all(v));
for(int j = 0; j < int(v.size()) - 1; ++j) if(v[j] == v[j + 1]) ok = 0;
if(ok){
if(ans > __builtin_popcount(mask)){
ans = __builtin_popcount(mask);
}
}
}
cout << ans;
return;
}
for(int i = 0; i < n; ++i) if(!vis[i]) dfs(i, 1);
cout << res;
}
int main(){
cin.tie(0); ios::sync_with_stdio(0);
int T = 1, aa;
// cin >> T;aa=T;
while(T--){
// cout << "Case #" << aa-T << ": ";
solve();
cout << '\n';
}
return 0;
}
Compilation message
polygon.cpp: In function 'int main()':
polygon.cpp:88:16: warning: unused variable 'aa' [-Wunused-variable]
88 | int T = 1, aa;
| ^~
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
37 ms |
56276 KB |
Execution killed with signal 6 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
35 ms |
56280 KB |
Execution killed with signal 6 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
35 ms |
56224 KB |
Execution killed with signal 6 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
37 ms |
56276 KB |
Execution killed with signal 6 |
2 |
Halted |
0 ms |
0 KB |
- |