#include <bits/stdc++.h>
using namespace std;
int const N=1e5+5;
map<string,int> mp;
int suc[N];
vector<int> lover[N];
vector<int> adj[N];
vector<int> cc[N];
int c=0;
int ccn[N];
int _dp[N],dp[N];
void dfs(int node){
ccn[node]=c;
cc[c].push_back(node);
for(auto i:adj[node])
if(ccn[i]==0)
dfs(i);
}
void LIS(int root){//largest_independent_set
// cout<<root<<endl;
for(auto i:lover[root])
if(i!=root)
LIS(i);
_dp[root]=1;
int maxx=0;
for(auto i:lover[root])
if(i!=root){
_dp[root]+=dp[i];
dp[root]+=dp[i];
maxx=max(maxx,_dp[i]-dp[i]);
}
dp[root]+=maxx;
}
int main(){
int n;
cin>>n;
string a,b;
int sz=1;
for (int i = 0; i < n; ++i)
{
cin>>a>>b;
if(mp[a]==0){
mp[a]=sz;
sz++;
}
if(mp[b]==0){
mp[b]=sz;
sz++;
}
// cout<<mp[a]<<' '<<mp[b]<<endl;
suc[mp[a]]=mp[b];
if(mp[a]==mp[b])
continue;
adj[mp[b]].push_back(mp[a]);
adj[mp[a]].push_back(mp[b]);
suc[mp[a]]=mp[b];
lover[mp[b]].push_back(mp[a]);
}
if(n%2){
cout<<-1<<endl;
return 0;
}
for (int i = 1; i <=n; ++i)
if(ccn[i]==0){
c++;
dfs(i);
}
int ans=0;
for (int i = 1; i <=c; ++i)
{
for(auto v:cc[i])
if(suc[v]==v){
LIS(v);
ans+=dp[v];
}
}
cout<<n-ans<<endl;
// for (int i = 1; i <=n; ++i)
// {
// cout<<dp[i]<<' '<<_dp[i]<<endl;
// }
return 0;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
7360 KB |
Output is correct |
2 |
Correct |
3 ms |
7380 KB |
Output is correct |
3 |
Correct |
3 ms |
7252 KB |
Output is correct |
4 |
Incorrect |
3 ms |
7252 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
7364 KB |
Output is correct |
2 |
Incorrect |
4 ms |
7296 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
402 ms |
24888 KB |
Output is correct |
2 |
Correct |
410 ms |
26272 KB |
Output is correct |
3 |
Correct |
204 ms |
21936 KB |
Output is correct |
4 |
Correct |
411 ms |
22488 KB |
Output is correct |
5 |
Correct |
427 ms |
29864 KB |
Output is correct |
6 |
Correct |
423 ms |
24220 KB |
Output is correct |
7 |
Correct |
406 ms |
24252 KB |
Output is correct |
8 |
Correct |
313 ms |
23980 KB |
Output is correct |
9 |
Correct |
389 ms |
23888 KB |
Output is correct |
10 |
Correct |
269 ms |
23240 KB |
Output is correct |
11 |
Correct |
3 ms |
7380 KB |
Output is correct |
12 |
Correct |
4 ms |
7364 KB |
Output is correct |
13 |
Correct |
5 ms |
7360 KB |
Output is correct |
14 |
Correct |
3 ms |
7380 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
7360 KB |
Output is correct |
2 |
Correct |
3 ms |
7380 KB |
Output is correct |
3 |
Correct |
3 ms |
7252 KB |
Output is correct |
4 |
Incorrect |
3 ms |
7252 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |