#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
using namespace std;
typedef long long ll;
const int N=100005,INF=1e9;
struct DSU{
int p[N],sz[N];
void init(int n){
iota(p,p+n+1,0);
fill(sz,sz+n+1,1);
}
int Find(int u){
return (p[u]==u?u:p[u]=Find(p[u]));
}
bool operator()(int u,int v){
u=Find(u);v=Find(v);
if(u==v)return 0;
if(sz[u]>sz[v])swap(u,v);
sz[v]+=sz[u];
p[u]=v;
return 1;
}
}dsu;
int n,root,special;
int dp[N][2][2][2][2];//cur,root,par,special
int p[N];
vector<vector<int>>adj(N);
void dfs(int v,int par){
p[v]=par;
for(auto u:adj[v]) {
if(u==par)continue;
dfs(u,v);
}
}
int solve(int v,int cur,int par,int rot,int sp){
int&ret=dp[v][cur][par][rot][sp];
if(~ret)return ret;
ret=INF;
bool flag=1;
if(v==root&&cur!=rot)flag=0;
if(v==special&&cur!=sp)flag=0;
if(v==special&&par&&rot)flag=0;
if(!flag)return ret;
bool covered=0;
if(par)covered=1;
if(v==root&&sp)covered=1;
if(v==special&&rot)covered=1;
ll sum=cur;
for(auto u:adj[v]){
if(u==p[v])continue;
sum+=solve(u,0,cur,rot,sp);
}
if(covered){
ret=min((ll)ret,sum);
}else{
for(auto u:adj[v]){
if(u==p[v])continue;
ll val=sum-solve(u,0,cur,rot,sp)+solve(u,1,cur,rot,sp);
ret=min((ll)ret,val);
}
}
return ret;
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
memset(dp,-1,sizeof(dp));
cin>>n;
dsu.init(n);
for(int i=0;i<n;i++){
int u,v;
cin>>u>>v;
if(!dsu(u,v)){
root=u;
special=v;
}else{
adj[u].push_back(v);
adj[v].push_back(u);
}
}
dfs(root,0);
int res=INF;
for(auto rot:{0,1})for(auto sp:{0,1}){
//cout<<rot<<" "<<sp<<" : "<<solve(root,rot,0,rot,sp)<<"\n";
res=min(res,solve(root,rot,0,rot,sp));
}
cout<<(res==INF?-1:res)<<"\n";
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
9052 KB |
Output is correct |
2 |
Correct |
1 ms |
9052 KB |
Output is correct |
3 |
Correct |
2 ms |
9052 KB |
Output is correct |
4 |
Correct |
2 ms |
9052 KB |
Output is correct |
5 |
Correct |
117 ms |
27268 KB |
Output is correct |
6 |
Correct |
126 ms |
27192 KB |
Output is correct |
7 |
Correct |
120 ms |
27384 KB |
Output is correct |
8 |
Correct |
150 ms |
27216 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
9308 KB |
Output is correct |
2 |
Correct |
2 ms |
9308 KB |
Output is correct |
3 |
Correct |
2 ms |
9228 KB |
Output is correct |
4 |
Correct |
3 ms |
9308 KB |
Output is correct |
5 |
Correct |
2 ms |
9048 KB |
Output is correct |
6 |
Correct |
2 ms |
9052 KB |
Output is correct |
7 |
Correct |
2 ms |
9052 KB |
Output is correct |
8 |
Correct |
2 ms |
9052 KB |
Output is correct |
9 |
Correct |
2 ms |
9048 KB |
Output is correct |
10 |
Correct |
2 ms |
9052 KB |
Output is correct |
11 |
Correct |
2 ms |
9052 KB |
Output is correct |
12 |
Correct |
2 ms |
9308 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
9308 KB |
Output is correct |
2 |
Correct |
2 ms |
9308 KB |
Output is correct |
3 |
Correct |
2 ms |
9228 KB |
Output is correct |
4 |
Correct |
3 ms |
9308 KB |
Output is correct |
5 |
Correct |
2 ms |
9048 KB |
Output is correct |
6 |
Correct |
2 ms |
9052 KB |
Output is correct |
7 |
Correct |
2 ms |
9052 KB |
Output is correct |
8 |
Correct |
2 ms |
9052 KB |
Output is correct |
9 |
Correct |
2 ms |
9048 KB |
Output is correct |
10 |
Correct |
2 ms |
9052 KB |
Output is correct |
11 |
Correct |
2 ms |
9052 KB |
Output is correct |
12 |
Correct |
2 ms |
9308 KB |
Output is correct |
13 |
Correct |
3 ms |
9304 KB |
Output is correct |
14 |
Correct |
3 ms |
9308 KB |
Output is correct |
15 |
Correct |
3 ms |
9308 KB |
Output is correct |
16 |
Correct |
3 ms |
9344 KB |
Output is correct |
17 |
Correct |
2 ms |
9304 KB |
Output is correct |
18 |
Correct |
3 ms |
9308 KB |
Output is correct |
19 |
Correct |
2 ms |
9308 KB |
Output is correct |
20 |
Correct |
3 ms |
9308 KB |
Output is correct |
21 |
Correct |
2 ms |
9560 KB |
Output is correct |
22 |
Correct |
2 ms |
9308 KB |
Output is correct |
23 |
Correct |
2 ms |
9308 KB |
Output is correct |
24 |
Correct |
3 ms |
9308 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
9052 KB |
Output is correct |
2 |
Correct |
1 ms |
9052 KB |
Output is correct |
3 |
Correct |
2 ms |
9052 KB |
Output is correct |
4 |
Correct |
2 ms |
9052 KB |
Output is correct |
5 |
Correct |
117 ms |
27268 KB |
Output is correct |
6 |
Correct |
126 ms |
27192 KB |
Output is correct |
7 |
Correct |
120 ms |
27384 KB |
Output is correct |
8 |
Correct |
150 ms |
27216 KB |
Output is correct |
9 |
Correct |
2 ms |
9308 KB |
Output is correct |
10 |
Correct |
2 ms |
9308 KB |
Output is correct |
11 |
Correct |
2 ms |
9228 KB |
Output is correct |
12 |
Correct |
3 ms |
9308 KB |
Output is correct |
13 |
Correct |
2 ms |
9048 KB |
Output is correct |
14 |
Correct |
2 ms |
9052 KB |
Output is correct |
15 |
Correct |
2 ms |
9052 KB |
Output is correct |
16 |
Correct |
2 ms |
9052 KB |
Output is correct |
17 |
Correct |
2 ms |
9048 KB |
Output is correct |
18 |
Correct |
2 ms |
9052 KB |
Output is correct |
19 |
Correct |
2 ms |
9052 KB |
Output is correct |
20 |
Correct |
2 ms |
9308 KB |
Output is correct |
21 |
Correct |
3 ms |
9304 KB |
Output is correct |
22 |
Correct |
3 ms |
9308 KB |
Output is correct |
23 |
Correct |
3 ms |
9308 KB |
Output is correct |
24 |
Correct |
3 ms |
9344 KB |
Output is correct |
25 |
Correct |
2 ms |
9304 KB |
Output is correct |
26 |
Correct |
3 ms |
9308 KB |
Output is correct |
27 |
Correct |
2 ms |
9308 KB |
Output is correct |
28 |
Correct |
3 ms |
9308 KB |
Output is correct |
29 |
Correct |
2 ms |
9560 KB |
Output is correct |
30 |
Correct |
2 ms |
9308 KB |
Output is correct |
31 |
Correct |
2 ms |
9308 KB |
Output is correct |
32 |
Correct |
3 ms |
9308 KB |
Output is correct |
33 |
Correct |
63 ms |
12892 KB |
Output is correct |
34 |
Correct |
79 ms |
12832 KB |
Output is correct |
35 |
Correct |
79 ms |
12888 KB |
Output is correct |
36 |
Correct |
72 ms |
12892 KB |
Output is correct |
37 |
Correct |
17 ms |
10076 KB |
Output is correct |
38 |
Correct |
74 ms |
12892 KB |
Output is correct |
39 |
Correct |
7 ms |
9564 KB |
Output is correct |
40 |
Correct |
64 ms |
12840 KB |
Output is correct |
41 |
Correct |
39 ms |
13608 KB |
Output is correct |
42 |
Correct |
50 ms |
13772 KB |
Output is correct |
43 |
Correct |
114 ms |
27216 KB |
Output is correct |
44 |
Correct |
74 ms |
20424 KB |
Output is correct |