#include <bits/stdc++.h>
using namespace std;
#define lli long long int
#define X first
#define Y second
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define pii pair<int, int>
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define test(args...) abc("[" + string(#args) + "]", args)
void abc() {cerr << endl;}
template <typename T, typename ...U> void abc(T a, U ...b) {
cerr << a << ' ', abc(b...);
}
template <typename T> void printv(T l, T r) {
while (l != r) cerr << *l << " \n"[++l == r];
}
const int mod = 1e9 + 7, N = 200000;
int dsu[N];
int Find(int x) {
if (x == dsu[x]) return x;
return dsu[x] = Find(dsu[x]);
}
bool Union(int u, int v) {
u = Find(u), v = Find(v);
if (u == v) return false;
dsu[u] = v;
return true;
}
int main () {
ios::sync_with_stdio(false);
cin.tie(0);
int n, _id = 0;
cin >> n;
if (n & 1) return cout << -1 << endl, 0;
map <string, int> m1;
auto get = [&](string s) {
if (m1.count(s)) return m1[s];
return m1[s] = _id++;
};
for (int i = 0; i < n; ++i) dsu[i] = i;
vector <vector <int>> adj(n);
vector <int> pt(n);
string s, t;
vector <pii> oth;
for (int i = 0; i < n; ++i) {
cin >> s >> t;
int u = get(s), v = get(t);
pt[u] = v;
if (Union(u, v)) adj[v].pb(u), adj[u].pb(v);
else oth.eb(v, u);
}
vector <int> cur;
vector <vector <int>> dp1(n, vector <int>(2, 0));
vector <vector <int>> dp2(n, vector <int>(2, 0));
// 0 not choose, 1 choose
vector <bool> vis(n, false);
int cnt = 0;
function<void(int, int, int)> dfs = [&](int v, int pa, int out) {
cnt++;
for (int u : adj[v]) if (u != pa) {
dfs(u, v, out);
dp1[v][0] += max(dp1[u][0], dp1[u][1]);
dp2[v][0] += max(dp2[u][0], dp2[u][1]);
}
for (int u : adj[v]) if (u != pa) {
dp1[v][1] = max(dp1[v][1], dp1[v][0] - max(dp1[u][0], dp1[u][1]) + dp1[u][0] + 1);
dp2[v][1] = max(dp2[v][1], dp2[v][0] - max(dp2[u][0], dp2[u][1]) + dp2[u][0] + 1);
}
if (v == out) dp2[v][1] = -1 << 30;
};
int ans = n;
for (pii A : oth) {
cnt = 0;
dfs(A.X, -1, A.Y);
if (A.X != A.Y) ans -= max({dp1[A.X][0], dp1[A.X][1], dp2[A.X][0] + (pt[A.X] == A.Y && pt[A.Y] == A.X ? 2 : 1)});
else ans -= max(dp1[A.X][0], dp1[A.X][1]);
}
cout << ans << endl;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
204 KB |
Output is correct |
2 |
Correct |
0 ms |
204 KB |
Output is correct |
3 |
Correct |
1 ms |
204 KB |
Output is correct |
4 |
Correct |
0 ms |
204 KB |
Output is correct |
5 |
Correct |
0 ms |
204 KB |
Output is correct |
6 |
Correct |
0 ms |
204 KB |
Output is correct |
7 |
Incorrect |
1 ms |
204 KB |
Output isn't correct |
8 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
204 KB |
Output is correct |
2 |
Correct |
1 ms |
204 KB |
Output is correct |
3 |
Correct |
0 ms |
204 KB |
Output is correct |
4 |
Incorrect |
361 ms |
34864 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
302 ms |
25544 KB |
Output is correct |
2 |
Correct |
326 ms |
27776 KB |
Output is correct |
3 |
Correct |
173 ms |
22996 KB |
Output is correct |
4 |
Correct |
1 ms |
204 KB |
Output is correct |
5 |
Correct |
317 ms |
35504 KB |
Output is correct |
6 |
Correct |
281 ms |
25384 KB |
Output is correct |
7 |
Correct |
297 ms |
25380 KB |
Output is correct |
8 |
Correct |
243 ms |
24976 KB |
Output is correct |
9 |
Correct |
260 ms |
25616 KB |
Output is correct |
10 |
Correct |
174 ms |
25836 KB |
Output is correct |
11 |
Correct |
0 ms |
204 KB |
Output is correct |
12 |
Correct |
1 ms |
204 KB |
Output is correct |
13 |
Correct |
1 ms |
204 KB |
Output is correct |
14 |
Correct |
1 ms |
204 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
204 KB |
Output is correct |
2 |
Correct |
0 ms |
204 KB |
Output is correct |
3 |
Correct |
1 ms |
204 KB |
Output is correct |
4 |
Correct |
0 ms |
204 KB |
Output is correct |
5 |
Correct |
0 ms |
204 KB |
Output is correct |
6 |
Correct |
0 ms |
204 KB |
Output is correct |
7 |
Incorrect |
1 ms |
204 KB |
Output isn't correct |
8 |
Halted |
0 ms |
0 KB |
- |