#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define pb push_back
#define fi first
#define se second
const int maxn5 = 3e5 + 10;
int a[maxn5], req[maxn5];
int dp[2][maxn5]; // dp[0 -> khodesh nabashad/ 1 -> bashad][v]
int sz[maxn5];
map <string, int> av;
bool mark[maxn5];
vector <int> adj[maxn5];
inline void dfs(int v){
//cout << "hello " << v << endl;
dp[0][v] = 0;
sz[v] = 1;
bool re = false;
for(auto u : adj[v]){
dfs(u);
sz[v] += sz[u];
dp[0][v] += dp[1][u] + (sz[u] % 2);
re = true;
}
if(!re){
dp[1][v] = 0;
return;
}
dp[1][v] = maxn5;
for(auto u : adj[v]){
int val = dp[0][v] - dp[1][u] - (sz[u] % 2);
val += dp[0][u] + (sz[u] % 2 == 0);
val++;
if(sz[v] % 2 == 1)
val--;
dp[1][v] = min(dp[1][v], val);
}
if(sz[v] % 2 == 0){
dp[0][v]--;
}
else{
dp[1][v] = min(dp[1][v], dp[0][v]);
}
//cout << v << ' ' << dp[0][v] << ' ' << dp[1][v] << endl;
return;
}
int main(){
ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
int n; cin >> n;
int ind = 0;
for(int i = 0; i < n; i++){
string s, t; cin >> s >> t;
if(av.find(s) == av.end())
av[s] = ind++;
if(av.find(t) == av.end())
av[t] = ind++;
if(t != s){
adj[av[t]].pb(av[s]);
mark[av[s]] = true;
}
}
/*
for(auto it = av.begin(); it != av.end(); it++)
cout << (it -> fi) << ' ' << (it -> se) << endl;
*/
if(n % 2 == 1)
return cout << -1 << endl, 0;
ll ans = 0;
for(int i = 0; i < n; i++) if(!mark[i]){
dfs(i);
ans += dp[1][i];
if(sz[i] % 2 == 1)
ans++;
}
cout << ans << endl;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
4 ms |
7368 KB |
Output is correct |
2 |
Correct |
4 ms |
7372 KB |
Output is correct |
3 |
Correct |
4 ms |
7372 KB |
Output is correct |
4 |
Incorrect |
4 ms |
7372 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
4 ms |
7372 KB |
Output is correct |
2 |
Correct |
4 ms |
7368 KB |
Output is correct |
3 |
Incorrect |
4 ms |
7372 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
223 ms |
20972 KB |
Output is correct |
2 |
Correct |
224 ms |
22880 KB |
Output is correct |
3 |
Correct |
108 ms |
18520 KB |
Output is correct |
4 |
Correct |
201 ms |
19016 KB |
Output is correct |
5 |
Correct |
228 ms |
28920 KB |
Output is correct |
6 |
Correct |
230 ms |
20196 KB |
Output is correct |
7 |
Correct |
211 ms |
20164 KB |
Output is correct |
8 |
Correct |
162 ms |
19712 KB |
Output is correct |
9 |
Correct |
204 ms |
19660 KB |
Output is correct |
10 |
Correct |
146 ms |
19000 KB |
Output is correct |
11 |
Correct |
4 ms |
7372 KB |
Output is correct |
12 |
Correct |
4 ms |
7372 KB |
Output is correct |
13 |
Correct |
4 ms |
7372 KB |
Output is correct |
14 |
Correct |
4 ms |
7372 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
4 ms |
7368 KB |
Output is correct |
2 |
Correct |
4 ms |
7372 KB |
Output is correct |
3 |
Correct |
4 ms |
7372 KB |
Output is correct |
4 |
Incorrect |
4 ms |
7372 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |