#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define F first
#define S second
#define pb push_back
#define endl '\n'
#define all(x) x.begin(),x.end()
#define yes cout<<"Yes"<<endl
#define no cout<<"No"<<endl
const int N = 2e5,mod = 1e9+7,INF = 1e9+7;
vector<int>v[N];
int head[N],par[N];
int root,special;
ll dp[N][2][2][2][2];
int st(int x)
{
if(x==head[x])return x;
return head[x] = st(head[x]);
}
void dfs (int x, int rod) {
par[x] = rod;
for (auto sus : v[x]) {
if (sus == rod) continue;
dfs(sus, x);
}
}
int calc (int x, int me, int up, int rt, int sp) {
if (dp[x][me][up][rt][sp] != -1) return dp[x][me][up][rt][sp];
ll res = INF;
bool ok = 1;
if (x == root && me != rt) ok = 0;
if (x == special && me != sp) ok = 0;
if (x == special && up && rt) ok = 0;
if (!ok) return dp[x][me][up][rt][sp] = INF;
bool covered = 0;
if (up) covered = 1;
if (x == root && sp) covered = 1;
if (x == special && rt) covered = 1;
ll sum = me;
for (auto sus : v[x]) {
if (sus == par[x]) continue;
sum += calc(sus, 0, me, rt, sp);
}
if (covered) {
res = min(res, sum);
} else {
for (auto sus : v[x]) {
if (sus == par[x]) continue;
ll val = sum - calc(sus, 0, me, rt, sp) + calc(sus, 1, me, rt, sp);
res = min(res, val);
}
}
return dp[x][me][up][rt][sp] = res;
}
int main()
{
ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
int n;
cin>>n;
for(int i = 0;i<=n;i++)
head[i] = i;
for(int i = 0;i<n;i++)
{
int a,b;
cin>>a>>b;
int pa = st(a);
int pb = st(b);
if(pa==pb)
{
root = b;
special = a;
}
else
{
head[pa] = pb;
v[a].pb(b);
v[b].pb(a);
}
}
dfs(root,0);
int ans = 1e18;
memset(dp,-1,sizeof dp);
for(int rt = 0;rt<=1;rt++)
{
for(int sp = 0;sp<=1;sp++)
{
ans = min(ans,calc(root,rt,0,rt,sp));
}
}
if(ans==1e18)
cout<<-1<<endl;
else
cout<<ans<<endl;
return 0;
}
/*
*/
Compilation message
Main.cpp: In function 'int main()':
Main.cpp:98:15: warning: overflow in conversion from 'double' to 'int' changes value from '1.0e+18' to '2147483647' [-Woverflow]
98 | int ans = 1e18;
| ^~~~
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
12 ms |
30036 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
15 ms |
30036 KB |
Output is correct |
2 |
Correct |
12 ms |
30008 KB |
Output is correct |
3 |
Correct |
13 ms |
30036 KB |
Output is correct |
4 |
Correct |
13 ms |
29984 KB |
Output is correct |
5 |
Incorrect |
13 ms |
30008 KB |
Output isn't correct |
6 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
15 ms |
30036 KB |
Output is correct |
2 |
Correct |
12 ms |
30008 KB |
Output is correct |
3 |
Correct |
13 ms |
30036 KB |
Output is correct |
4 |
Correct |
13 ms |
29984 KB |
Output is correct |
5 |
Incorrect |
13 ms |
30008 KB |
Output isn't correct |
6 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
12 ms |
30036 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |