#include <iostream>
#include <vector>
#include <set>
#include <map>
#include <algorithm>
#include <string>
#include <sstream>
#include <fstream>
#include <cmath>
#include <queue>
#include <stack>
#include <unordered_map>
#include <unordered_set>
#include <bitset>
#include <bits/stdc++.h>
#define lcm(a,b) (a/__gcd(a,b))*b
#define jumanji ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define pb push_back
#define F first
#define S second
#define int long long
#define vi vector<int>
#define ll long long
using namespace std;
const int tam=1e5+5;
vector<vi>G;
int A;
int B;
bool vis[tam];
//find two nodes inside a cycle
void dfs(int u,int p){
vis[u]=1;
for(auto v:G[u]){
if(v==p)continue;
if(vis[v]){
A=u;
B=v;
return;
}
dfs(v,u);
}
}
//dp on tree
int dp[tam][2][2][2][2];
int f(int nodo,int color, int cP,int cA, int cB, int p=0){
int &ans=dp[nodo][color][cP][cA][cB];
if(nodo==A){
if(color!=cA)return ans=1e6;
}
if(nodo==B){
if(color!=cB)return ans=1e6;
}
if(nodo==B){
if(cA and cP and p!=A)return ans=1e6;
if(cA==0 and cP==0)return ans=1e6;
}
if(G[nodo].size()==1 and nodo!=A){
return 0;
}
if(ans!=-1)return ans;
ans=1e6;
bool ok=true;
if(nodo==B && cA)ok=false;
if(cP or ok==false){
int sum=0;
for(auto v:G[nodo]){
if(v==p)continue;
sum+=f(v,0,color,cA,cB,nodo);
}
ans=min(ans,sum);
}
//cP == 0 entonces exactamente un hijo tiene que ser 1
if(cP==0 && ok){
// cout<<"mierda "<<nodo<<endl;
int sum=0;
int puedo=0;
int cant=0;
for(auto v:G[nodo]){
if(v==p)continue;
cant++;
int curr=f(v,0,color,cA,cB,nodo);
sum+=curr;
if(curr==1e6)continue;
puedo++;
}
if(cant-puedo>1)return ans=1e6;
int diff=cant-puedo;
for(auto v:G[nodo]){
if(v==p)continue;
// cout<<nodo<<" "<<v<<" "<<endl;
//quiero pintar de 1
int curr=f(v,1,color,cA,cB,nodo);
int curr0=f(v,0,color,cA,cB,nodo);
if(curr==1e6)continue;
if(diff==0){
ans=min(ans,sum-curr+curr0+1);
}else{
// cout<<nodo<<" "<<sum-curr0+curr+1<<endl;
if(curr0!=1e6)continue;
ans=min(ans,sum-curr0+curr+1);
}
}
}
// cout<<nodo<<" = "<<ans<<endl;
return ans;
}
signed main(){
jumanji
memset(dp,-1,sizeof dp);
int n,a,b;
cin>>n;
G.assign(n+1,vi());
vector<pair<int,int>>edges;
for(int i=0;i<=n;i++){
cin>>a>>b;
G[a].pb(b);
G[b].pb(a);
edges.pb({a,b});
}
dfs(1,0);
G.assign(n+1,vi());
for(auto e:edges){
if(e.F==A and e.S==B)continue;
if(e.F==B and e.S==A)continue;
// cout<<e.F<<" f "<<e.S<<endl;
G[e.F].pb(e.S);
G[e.S].pb(e.F);
}
//ambos 1s
int res=1e6;
// cout<<f(4,0,0,1,0,3)<<endl;
// return 0;
for(int i=0;i<2;i++){
for(int j=0;j<2;j++){
int curr=f(A,i,j,i,j)+i;
res=min(res,curr);
// if(curr<=2){
// cout<<i<<" "<<j<<endl;
// cout<<curr<<endl;
// return 0;
// }
}
}
// cout<<A<<" "<<B<<endl;
if(res==1e6){
cout <<-1<<endl;
}else{
cout<<res<<endl;
}
return 0;
}
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
6 ms |
12756 KB |
Output is correct |
| 2 |
Correct |
6 ms |
12856 KB |
Output is correct |
| 3 |
Correct |
5 ms |
12856 KB |
Output is correct |
| 4 |
Correct |
6 ms |
12852 KB |
Output is correct |
| 5 |
Incorrect |
199 ms |
34328 KB |
Output isn't correct |
| 6 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
5 ms |
12756 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
5 ms |
12756 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
6 ms |
12756 KB |
Output is correct |
| 2 |
Correct |
6 ms |
12856 KB |
Output is correct |
| 3 |
Correct |
5 ms |
12856 KB |
Output is correct |
| 4 |
Correct |
6 ms |
12852 KB |
Output is correct |
| 5 |
Incorrect |
199 ms |
34328 KB |
Output isn't correct |
| 6 |
Halted |
0 ms |
0 KB |
- |
