#include <bits/stdc++.h>
#define speed ios_base::sync_with_stdio(0); cin.tie(0)
#define all(x) (x).begin(),(x).end()
#define F first
#define S second
using namespace std;
typedef long long ll;
typedef double db;
typedef long double ldb;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
const ll MAX=1e5+10,P=998244353;
const ll INF=0x3f3f3f3f,oo=0x3f3f3f3f3f3f3f3f;
int n;
vector<pair<string,string> > eg;
int G[MAX];
vector<int> cptG[MAX];
int dp[MAX][2];
void dfs2(int v,int p) {
if (cptG[v].size()==1) {
dp[v][0]=0;
dp[v][1]=1;
return;
}
dp[v][0]=0;
for (int i:cptG[v]) {
if (i==p) continue;
dfs2(i,v);
dp[v][0]+=dp[i][1];
}
dp[v][1]=INF;
for (int i:cptG[v]) {
if (i==p) continue;
dp[v][1]=min(dp[v][1],dp[v][0]-dp[i][1]+dp[i][0]+1);
}
// cout<<v<<" "<<dp[v][0]<<" "<<dp[v][1]<<"\n";
}
int main() {
speed;
cin>>n;
vector<string> dct;
for (int i=0;i<n;i++) {
string a,b;
cin>>a>>b;
eg.emplace_back(a,b);
dct.push_back(a);
dct.push_back(b);
}
sort(all(dct));
dct.resize(unique(all(dct))-dct.begin());
vector<int> lvd(n,0);
for (int i=0;i<n;i++) {
auto [a,b]=eg[i];
int va=lower_bound(all(dct),a)-dct.begin();
int vb=lower_bound(all(dct),b)-dct.begin();
G[va]=vb;
cptG[va].push_back(vb);
cptG[vb].push_back(va);
lvd[vb]++;
}
bool alllvd=true;
for (int i=0;i<n;i++) {
if (lvd[i]!=1) {
alllvd=false;
break;
}
}
if (n&1) {
cout<<"-1\n";
return 0;
}
if (n<=20) {
int ans=n;
for (int st=0;st<(1<<n);st++) {
bool flag=true;
vector<int> cnt(n,0);
for (int i=0;i<n;i++) {
if (st&(1<<i)) continue;
if (G[i]==i) {
flag=false;
break;
}
int tgt=G[i];
if (G[tgt]==i) continue;
if (st&(1<<tgt)) {
if (cnt[tgt]==0) {
cnt[tgt]++;
continue;
}
}
flag=false;
break;
}
// if (flag) cout<<st<<"\n";
if (flag) ans=min(ans,__builtin_popcount(st));
}
cout<<ans<<"\n";
} else if (alllvd) {
vector<bool> vis(n,0);
int ans=0;
for (int i=0;i<n;i++) {
if (vis[i]) continue;
int now=i;
int st=i;
int sz=1;
vis[i]=true;
while (G[now]!=st) {
// cout<<now<<" ";
sz++;
now=G[now];
vis[now]=true;
}
if (sz==2) continue;
ans+=(sz+1)>>1;
}
cout<<ans<<"\n";
} else {
vector<int> sz(n);
int ans=0;
for (int i=0;i<n;i++) {
if (G[i]==i) {
dfs2(i,i);
ans+=dp[i][1];
}
}
cout<<ans<<"\n";
}
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
29 ms |
3420 KB |
Output is correct |
2 |
Correct |
23 ms |
3420 KB |
Output is correct |
3 |
Correct |
26 ms |
3420 KB |
Output is correct |
4 |
Correct |
1 ms |
3352 KB |
Output is correct |
5 |
Correct |
1 ms |
3416 KB |
Output is correct |
6 |
Correct |
1 ms |
3420 KB |
Output is correct |
7 |
Correct |
27 ms |
3436 KB |
Output is correct |
8 |
Correct |
28 ms |
3420 KB |
Output is correct |
9 |
Correct |
25 ms |
3420 KB |
Output is correct |
10 |
Correct |
31 ms |
3420 KB |
Output is correct |
11 |
Correct |
30 ms |
3436 KB |
Output is correct |
12 |
Correct |
1 ms |
3420 KB |
Output is correct |
13 |
Correct |
2 ms |
3380 KB |
Output is correct |
14 |
Correct |
1 ms |
3416 KB |
Output is correct |
15 |
Correct |
1 ms |
3420 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
3420 KB |
Output is correct |
2 |
Correct |
1 ms |
3420 KB |
Output is correct |
3 |
Correct |
1 ms |
3420 KB |
Output is correct |
4 |
Correct |
151 ms |
23940 KB |
Output is correct |
5 |
Correct |
132 ms |
23748 KB |
Output is correct |
6 |
Correct |
126 ms |
25232 KB |
Output is correct |
7 |
Correct |
127 ms |
24188 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
139 ms |
25376 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
29 ms |
3420 KB |
Output is correct |
2 |
Correct |
23 ms |
3420 KB |
Output is correct |
3 |
Correct |
26 ms |
3420 KB |
Output is correct |
4 |
Correct |
1 ms |
3352 KB |
Output is correct |
5 |
Correct |
1 ms |
3416 KB |
Output is correct |
6 |
Correct |
1 ms |
3420 KB |
Output is correct |
7 |
Correct |
27 ms |
3436 KB |
Output is correct |
8 |
Correct |
28 ms |
3420 KB |
Output is correct |
9 |
Correct |
25 ms |
3420 KB |
Output is correct |
10 |
Correct |
31 ms |
3420 KB |
Output is correct |
11 |
Correct |
30 ms |
3436 KB |
Output is correct |
12 |
Correct |
1 ms |
3420 KB |
Output is correct |
13 |
Correct |
2 ms |
3380 KB |
Output is correct |
14 |
Correct |
1 ms |
3416 KB |
Output is correct |
15 |
Correct |
1 ms |
3420 KB |
Output is correct |
16 |
Correct |
1 ms |
3420 KB |
Output is correct |
17 |
Correct |
1 ms |
3420 KB |
Output is correct |
18 |
Correct |
1 ms |
3420 KB |
Output is correct |
19 |
Correct |
151 ms |
23940 KB |
Output is correct |
20 |
Correct |
132 ms |
23748 KB |
Output is correct |
21 |
Correct |
126 ms |
25232 KB |
Output is correct |
22 |
Correct |
127 ms |
24188 KB |
Output is correct |
23 |
Incorrect |
139 ms |
25376 KB |
Output isn't correct |
24 |
Halted |
0 ms |
0 KB |
- |