#include<bits/stdc++.h>
using namespace std;
map<string,int>mp;
vector<int>v[100005];
vector<int>rt;
int dp[100005][2];
int dp2[100005][2];
int sz[100005];
int vis[100005];
int lp=0;
int p[100005];
int com[100005];
int fp(int a){return p[a]==a?a:p[a]=fp(p[a]);}
void un(int a,int b){p[fp(b)]=fp(a);}
int lv[100005];
void dfs(int u,int rt){
//cerr<<"node"<<u<<"\n";
if(vis[u])return;
vis[u]=1;
int sum=0;
sz[u]=1;
for(auto x:v[u]){
if(vis[x])continue;
dfs(x,rt);
sz[u]+=sz[x];
sum+=dp[x][0];
}
dp[u][1]=sum;
for(auto x:v[u])if(x!=rt)dp[u][0]=max(sum-dp[x][0]+dp[x][1]+1,dp[u][0]);
}
void dfs2(int u,int p=0){
lv[u]=lv[p]+1;
if(u==lp)return;
int sum=0;
for(auto x:v[u]){
dfs2(x,u);
sum+=dp2[x][0];
}
dp2[u][1]=sum;
for(auto x:v[u])if(x!=lp)dp2[u][0]=max(sum-dp2[x][0]+dp2[x][1]+1,dp2[u][0]);
//cerr<<u<<" "<<dp[u][1]<<"\n";
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(0);
int n;cin>>n;
int cur=0;
for(int i=1;i<=n;i++)p[i]=i;
for(int i=0;i<n;i++){
string a,b;cin>>a>>b;
if(mp[a]==0)cur++,mp[a]=cur;
if(mp[b]==0)cur++,mp[b]=cur;
//cerr<<a<<" "<<mp[a]<<","<<b<<" "<<mp[b]<<"\n";
if(mp[a]==mp[b])rt.push_back(mp[a])/*,cerr<<"root\n"*/;
else if(fp(mp[a])==fp(mp[b]))rt.push_back(mp[a]),com[mp[a]]=mp[b]/*,cerr<<"one loop\n"*/;
else v[mp[b]].push_back(mp[a])/*,cerr<<"nothing\n"*/;
un(mp[a],mp[b]);
}
if(n%2==1){
cout<<"-1";
return 0;
}
/*for(int i=1;i<=n;i++){
cerr<<i<<": ";
for(auto x:v[i])cerr<<x<<" ";
cerr<<"\n";
}*/
int ans=0;
//for(auto x:rt)cerr<<x<<" ";
//cerr<<"\n";
for(auto x:rt){
//cerr<<x<<":\n";
dfs(x,x);
//cerr<<dp[x][0]<<" "<<dp[x][1]<<"\n";
int temp=(max(dp[x][0],dp[x][1])+sz[x]-2*max(dp[x][0],dp[x][1]));
//cerr<<"temp:"<<temp<<"\n";
if(com[x]!=0){
//cerr<<"loop\n";
lp=com[x];
//cerr<<lp<<"\n";
//cerr<<"info:\n";
dfs2(x);
//cerr<<"info:\n";
////for(int i=0;i<n;i++)cerr<<dp2[i][1]<<" ";
//cerr<<"\n";
//cerr<<dp2[x][1]<<" "<<dp[lp][1]<<"\n";
int pp=dp2[x][1]+dp[lp][1]+1;
//cerr<<pp<<"\n";
//cerr<<lv[lp]<<"\n";
if(sz[x]!=2)ans+=min(temp,pp+(sz[x]-pp*2)-(lv[lp]==2?1:0));
}else ans+=(max(dp[x][0],dp[x][1])+sz[x]-2*max(dp[x][0],dp[x][1]));
//cerr<<max(dp[x][0],dp[x][1])<<"\n";
}
cout<<ans;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
5980 KB |
Output is correct |
2 |
Correct |
2 ms |
5980 KB |
Output is correct |
3 |
Correct |
2 ms |
5980 KB |
Output is correct |
4 |
Correct |
2 ms |
5980 KB |
Output is correct |
5 |
Correct |
1 ms |
5980 KB |
Output is correct |
6 |
Correct |
1 ms |
5980 KB |
Output is correct |
7 |
Correct |
2 ms |
5976 KB |
Output is correct |
8 |
Correct |
2 ms |
5980 KB |
Output is correct |
9 |
Correct |
2 ms |
5980 KB |
Output is correct |
10 |
Correct |
2 ms |
5976 KB |
Output is correct |
11 |
Correct |
2 ms |
5980 KB |
Output is correct |
12 |
Correct |
2 ms |
5980 KB |
Output is correct |
13 |
Correct |
2 ms |
6128 KB |
Output is correct |
14 |
Correct |
1 ms |
5980 KB |
Output is correct |
15 |
Correct |
2 ms |
5980 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
2 ms |
5976 KB |
Output is correct |
2 |
Correct |
2 ms |
5976 KB |
Output is correct |
3 |
Correct |
2 ms |
5980 KB |
Output is correct |
4 |
Correct |
278 ms |
24028 KB |
Output is correct |
5 |
Correct |
259 ms |
16724 KB |
Output is correct |
6 |
Correct |
280 ms |
24912 KB |
Output is correct |
7 |
Correct |
246 ms |
19032 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
263 ms |
16096 KB |
Output is correct |
2 |
Correct |
257 ms |
18260 KB |
Output is correct |
3 |
Correct |
169 ms |
14196 KB |
Output is correct |
4 |
Correct |
258 ms |
17492 KB |
Output is correct |
5 |
Correct |
276 ms |
24148 KB |
Output is correct |
6 |
Correct |
298 ms |
15340 KB |
Output is correct |
7 |
Correct |
284 ms |
15440 KB |
Output is correct |
8 |
Correct |
210 ms |
15188 KB |
Output is correct |
9 |
Correct |
242 ms |
14916 KB |
Output is correct |
10 |
Correct |
179 ms |
14188 KB |
Output is correct |
11 |
Correct |
2 ms |
5976 KB |
Output is correct |
12 |
Correct |
2 ms |
5980 KB |
Output is correct |
13 |
Correct |
2 ms |
5980 KB |
Output is correct |
14 |
Correct |
1 ms |
5976 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
5980 KB |
Output is correct |
2 |
Correct |
2 ms |
5980 KB |
Output is correct |
3 |
Correct |
2 ms |
5980 KB |
Output is correct |
4 |
Correct |
2 ms |
5980 KB |
Output is correct |
5 |
Correct |
1 ms |
5980 KB |
Output is correct |
6 |
Correct |
1 ms |
5980 KB |
Output is correct |
7 |
Correct |
2 ms |
5976 KB |
Output is correct |
8 |
Correct |
2 ms |
5980 KB |
Output is correct |
9 |
Correct |
2 ms |
5980 KB |
Output is correct |
10 |
Correct |
2 ms |
5976 KB |
Output is correct |
11 |
Correct |
2 ms |
5980 KB |
Output is correct |
12 |
Correct |
2 ms |
5980 KB |
Output is correct |
13 |
Correct |
2 ms |
6128 KB |
Output is correct |
14 |
Correct |
1 ms |
5980 KB |
Output is correct |
15 |
Correct |
2 ms |
5980 KB |
Output is correct |
16 |
Correct |
2 ms |
5976 KB |
Output is correct |
17 |
Correct |
2 ms |
5976 KB |
Output is correct |
18 |
Correct |
2 ms |
5980 KB |
Output is correct |
19 |
Correct |
278 ms |
24028 KB |
Output is correct |
20 |
Correct |
259 ms |
16724 KB |
Output is correct |
21 |
Correct |
280 ms |
24912 KB |
Output is correct |
22 |
Correct |
246 ms |
19032 KB |
Output is correct |
23 |
Correct |
263 ms |
16096 KB |
Output is correct |
24 |
Correct |
257 ms |
18260 KB |
Output is correct |
25 |
Correct |
169 ms |
14196 KB |
Output is correct |
26 |
Correct |
258 ms |
17492 KB |
Output is correct |
27 |
Correct |
276 ms |
24148 KB |
Output is correct |
28 |
Correct |
298 ms |
15340 KB |
Output is correct |
29 |
Correct |
284 ms |
15440 KB |
Output is correct |
30 |
Correct |
210 ms |
15188 KB |
Output is correct |
31 |
Correct |
242 ms |
14916 KB |
Output is correct |
32 |
Correct |
179 ms |
14188 KB |
Output is correct |
33 |
Correct |
2 ms |
5976 KB |
Output is correct |
34 |
Correct |
2 ms |
5980 KB |
Output is correct |
35 |
Correct |
2 ms |
5980 KB |
Output is correct |
36 |
Correct |
1 ms |
5976 KB |
Output is correct |
37 |
Correct |
274 ms |
16980 KB |
Output is correct |
38 |
Correct |
263 ms |
16980 KB |
Output is correct |
39 |
Correct |
265 ms |
15824 KB |
Output is correct |
40 |
Correct |
279 ms |
15620 KB |
Output is correct |
41 |
Correct |
271 ms |
15564 KB |
Output is correct |
42 |
Correct |
254 ms |
15956 KB |
Output is correct |
43 |
Correct |
272 ms |
15996 KB |
Output is correct |
44 |
Correct |
282 ms |
16152 KB |
Output is correct |
45 |
Correct |
261 ms |
15956 KB |
Output is correct |
46 |
Correct |
280 ms |
16096 KB |
Output is correct |
47 |
Correct |
282 ms |
15112 KB |
Output is correct |
48 |
Correct |
276 ms |
16452 KB |
Output is correct |
49 |
Correct |
270 ms |
18236 KB |
Output is correct |
50 |
Correct |
167 ms |
14284 KB |
Output is correct |
51 |
Correct |
256 ms |
17916 KB |
Output is correct |
52 |
Correct |
319 ms |
24320 KB |
Output is correct |
53 |
Correct |
265 ms |
15724 KB |
Output is correct |
54 |
Correct |
243 ms |
15444 KB |
Output is correct |
55 |
Correct |
210 ms |
15212 KB |
Output is correct |
56 |
Correct |
256 ms |
15084 KB |
Output is correct |
57 |
Correct |
185 ms |
14280 KB |
Output is correct |
58 |
Correct |
2 ms |
5976 KB |
Output is correct |
59 |
Correct |
1 ms |
5980 KB |
Output is correct |
60 |
Correct |
1 ms |
5976 KB |
Output is correct |
61 |
Correct |
1 ms |
5976 KB |
Output is correct |
62 |
Correct |
1 ms |
5976 KB |
Output is correct |
63 |
Correct |
2 ms |
5976 KB |
Output is correct |
64 |
Correct |
2 ms |
5980 KB |
Output is correct |
65 |
Correct |
311 ms |
24000 KB |
Output is correct |
66 |
Correct |
273 ms |
16764 KB |
Output is correct |
67 |
Correct |
273 ms |
24972 KB |
Output is correct |
68 |
Correct |
247 ms |
19072 KB |
Output is correct |
69 |
Correct |
1 ms |
5976 KB |
Output is correct |
70 |
Correct |
2 ms |
5980 KB |
Output is correct |
71 |
Correct |
2 ms |
5980 KB |
Output is correct |
72 |
Correct |
1 ms |
5980 KB |
Output is correct |
73 |
Correct |
2 ms |
5980 KB |
Output is correct |
74 |
Correct |
2 ms |
5980 KB |
Output is correct |
75 |
Correct |
2 ms |
5976 KB |
Output is correct |
76 |
Correct |
2 ms |
5980 KB |
Output is correct |
77 |
Correct |
1 ms |
5976 KB |
Output is correct |
78 |
Correct |
1 ms |
5980 KB |
Output is correct |
79 |
Correct |
2 ms |
5976 KB |
Output is correct |
80 |
Correct |
2 ms |
5980 KB |
Output is correct |
81 |
Correct |
1 ms |
5980 KB |
Output is correct |
82 |
Correct |
2 ms |
5980 KB |
Output is correct |
83 |
Correct |
2 ms |
5980 KB |
Output is correct |