#include <bits/stdc++.h>
#pragma GCC optimize("O3,no-stack-protector,unroll-loops")
#pragma GCC target("avx2,fma")
#define rep(i,l,r) for (int i = l; i < r; i++)
#define repr(i,r,l) for (int i = r; i >= l; i--)
#define X first
#define Y second
#define pb push_back
#define endl '\n'
#define debug(x) cerr << #x << " : " << x << endl;
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int,int> pll;
typedef pair<long double,long double> pld;
const long long int N = 2e5+10,mod = 1e9+7,inf = 1e9,sq = 700,sig = 26;
inline int mkay(int a,int b){
if (a+b >= mod) return a+b-mod;
if (a+b < 0) return a+b+mod;
return a+b;
}
inline int poww(int n,int k){
int c = 1;
while (k){
if (k&1) c = (1ll*c*n)%mod;
n = (1ll*n*n)%mod;
k >>= 1;
}
return c;
}
map<string,int> mp;
vector<int> in[N],out[N];
int o,ans;
bool vis[N];
int mark[N],comp[N],p[N];
bool b[N];
void sfd(int v){
for (int u : in[v]){
if (u == v || mark[u] == 2) continue;
sfd(u);
if (!vis[v] && !vis[u]){
vis[v] = 1;
p[v] = u;
p[u] = v;
vis[u] = 1;
ans++;
o--;
}
}
if (!vis[v])
o++;
else if (mark[v] == 2)
b[comp[v]] = 1;
}
void dfs(int v,int t){
comp[v] = t;
for (int u : out[v]) if (!comp[u]) dfs(u,t);
for (int u : in[v]) if (!comp[u]) dfs(u,t);
}
int main(){
ios :: sync_with_stdio(0); cin.tie(0);cout.tie(0);
int n;
cin >> n;
if(n&1){
cout << -1;
return 0;
}
set<string> st;
int sz = 0;
rep(i,1,n+1){
string s,t;
cin >> s >> t;
if (st.find(s) == st.end()){
sz++;
mp[s] = sz;
st.insert(s);
}
if (st.find(t) == st.end()){
sz++;
mp[t] = sz;
st.insert(t);
}
in[mp[t]].pb(mp[s]);
out[mp[s]].pb(mp[t]);
}
int t = 0;
rep(i,1,n+1){
if(comp[i]) continue;
int v = i;
while (mark[v] == 0){
mark[v] = 1;
v = out[v][0];
}
int u = v;
while (mark[u] != 2){
mark[u] = 2;
u = out[u][0];
}
t++;
dfs(u,t);
}
rep(i,1,n+1)
if (!vis[i] && mark[i] == 2)
sfd(i);
rep(i,1,n+1){
if (mark[i] != 2) continue;
if (out[out[i][0]][0] == i && i != out[i][0]){
if (i > out[i][0]) continue;
int v = out[i][0];
if (!vis[i] && !vis[v])
o -= 2;
else if (vis[i] && vis[v])
continue;
else
ans--;
continue;
}
if (!b[comp[i]]){
int s = 1;
int v = out[i][0];
while(v != i){
s++;
v = out[v][0];
vis[v] = 1;
}
if (s == 2) o -= 2;
else{
if (s&1) o -= (s-1);
else o -= s;
ans += s/2;
}
b[comp[i]] = 1;
continue;
}
if (!vis[i] || vis[out[i][0]]) continue;
int v = out[i][0];
while (vis[v] != 1){
if (!vis[out[v][0]]){
vis[v] = 1;
vis[out[v][0]] = 1;
p[v] = out[v][0];
p[out[v][0]] = v;
ans ++;
o -= 2;
v = out[out[v][0]][0];
}
else break;
}
}
cout << o+ans;
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
5 ms |
9676 KB |
Output is correct |
2 |
Correct |
5 ms |
9676 KB |
Output is correct |
3 |
Correct |
6 ms |
9708 KB |
Output is correct |
4 |
Correct |
6 ms |
9668 KB |
Output is correct |
5 |
Correct |
5 ms |
9676 KB |
Output is correct |
6 |
Correct |
5 ms |
9676 KB |
Output is correct |
7 |
Correct |
6 ms |
9712 KB |
Output is correct |
8 |
Correct |
6 ms |
9676 KB |
Output is correct |
9 |
Correct |
5 ms |
9644 KB |
Output is correct |
10 |
Correct |
5 ms |
9676 KB |
Output is correct |
11 |
Correct |
6 ms |
9708 KB |
Output is correct |
12 |
Correct |
5 ms |
9676 KB |
Output is correct |
13 |
Correct |
6 ms |
9712 KB |
Output is correct |
14 |
Correct |
5 ms |
9708 KB |
Output is correct |
15 |
Correct |
7 ms |
9676 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
5 ms |
9676 KB |
Output is correct |
2 |
Correct |
6 ms |
9712 KB |
Output is correct |
3 |
Correct |
5 ms |
9676 KB |
Output is correct |
4 |
Correct |
456 ms |
52300 KB |
Output is correct |
5 |
Correct |
376 ms |
34616 KB |
Output is correct |
6 |
Correct |
481 ms |
55004 KB |
Output is correct |
7 |
Correct |
5 ms |
9676 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
364 ms |
34244 KB |
Output is correct |
2 |
Correct |
393 ms |
36384 KB |
Output is correct |
3 |
Correct |
283 ms |
34628 KB |
Output is correct |
4 |
Correct |
5 ms |
9676 KB |
Output is correct |
5 |
Correct |
381 ms |
42204 KB |
Output is correct |
6 |
Correct |
367 ms |
33196 KB |
Output is correct |
7 |
Correct |
344 ms |
33616 KB |
Output is correct |
8 |
Correct |
313 ms |
33820 KB |
Output is correct |
9 |
Correct |
321 ms |
32864 KB |
Output is correct |
10 |
Correct |
239 ms |
31444 KB |
Output is correct |
11 |
Correct |
5 ms |
9676 KB |
Output is correct |
12 |
Correct |
5 ms |
9676 KB |
Output is correct |
13 |
Correct |
5 ms |
9676 KB |
Output is correct |
14 |
Correct |
5 ms |
9676 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
5 ms |
9676 KB |
Output is correct |
2 |
Correct |
5 ms |
9676 KB |
Output is correct |
3 |
Correct |
6 ms |
9708 KB |
Output is correct |
4 |
Correct |
6 ms |
9668 KB |
Output is correct |
5 |
Correct |
5 ms |
9676 KB |
Output is correct |
6 |
Correct |
5 ms |
9676 KB |
Output is correct |
7 |
Correct |
6 ms |
9712 KB |
Output is correct |
8 |
Correct |
6 ms |
9676 KB |
Output is correct |
9 |
Correct |
5 ms |
9644 KB |
Output is correct |
10 |
Correct |
5 ms |
9676 KB |
Output is correct |
11 |
Correct |
6 ms |
9708 KB |
Output is correct |
12 |
Correct |
5 ms |
9676 KB |
Output is correct |
13 |
Correct |
6 ms |
9712 KB |
Output is correct |
14 |
Correct |
5 ms |
9708 KB |
Output is correct |
15 |
Correct |
7 ms |
9676 KB |
Output is correct |
16 |
Correct |
5 ms |
9676 KB |
Output is correct |
17 |
Correct |
6 ms |
9712 KB |
Output is correct |
18 |
Correct |
5 ms |
9676 KB |
Output is correct |
19 |
Correct |
456 ms |
52300 KB |
Output is correct |
20 |
Correct |
376 ms |
34616 KB |
Output is correct |
21 |
Correct |
481 ms |
55004 KB |
Output is correct |
22 |
Correct |
5 ms |
9676 KB |
Output is correct |
23 |
Correct |
364 ms |
34244 KB |
Output is correct |
24 |
Correct |
393 ms |
36384 KB |
Output is correct |
25 |
Correct |
283 ms |
34628 KB |
Output is correct |
26 |
Correct |
5 ms |
9676 KB |
Output is correct |
27 |
Correct |
381 ms |
42204 KB |
Output is correct |
28 |
Correct |
367 ms |
33196 KB |
Output is correct |
29 |
Correct |
344 ms |
33616 KB |
Output is correct |
30 |
Correct |
313 ms |
33820 KB |
Output is correct |
31 |
Correct |
321 ms |
32864 KB |
Output is correct |
32 |
Correct |
239 ms |
31444 KB |
Output is correct |
33 |
Correct |
5 ms |
9676 KB |
Output is correct |
34 |
Correct |
5 ms |
9676 KB |
Output is correct |
35 |
Correct |
5 ms |
9676 KB |
Output is correct |
36 |
Correct |
5 ms |
9676 KB |
Output is correct |
37 |
Correct |
397 ms |
34756 KB |
Output is correct |
38 |
Correct |
354 ms |
37012 KB |
Output is correct |
39 |
Correct |
351 ms |
33724 KB |
Output is correct |
40 |
Correct |
372 ms |
33336 KB |
Output is correct |
41 |
Correct |
347 ms |
33348 KB |
Output is correct |
42 |
Correct |
357 ms |
33800 KB |
Output is correct |
43 |
Correct |
364 ms |
33828 KB |
Output is correct |
44 |
Correct |
375 ms |
33928 KB |
Output is correct |
45 |
Correct |
363 ms |
33892 KB |
Output is correct |
46 |
Correct |
384 ms |
33864 KB |
Output is correct |
47 |
Correct |
333 ms |
33028 KB |
Output is correct |
48 |
Correct |
383 ms |
34244 KB |
Output is correct |
49 |
Correct |
392 ms |
36188 KB |
Output is correct |
50 |
Correct |
284 ms |
34676 KB |
Output is correct |
51 |
Correct |
7 ms |
9804 KB |
Output is correct |
52 |
Correct |
405 ms |
42208 KB |
Output is correct |
53 |
Correct |
361 ms |
33220 KB |
Output is correct |
54 |
Correct |
342 ms |
33616 KB |
Output is correct |
55 |
Correct |
322 ms |
34040 KB |
Output is correct |
56 |
Correct |
330 ms |
32648 KB |
Output is correct |
57 |
Correct |
224 ms |
31376 KB |
Output is correct |
58 |
Correct |
5 ms |
9676 KB |
Output is correct |
59 |
Correct |
5 ms |
9716 KB |
Output is correct |
60 |
Correct |
5 ms |
9676 KB |
Output is correct |
61 |
Correct |
5 ms |
9676 KB |
Output is correct |
62 |
Correct |
5 ms |
9676 KB |
Output is correct |
63 |
Correct |
5 ms |
9676 KB |
Output is correct |
64 |
Correct |
5 ms |
9676 KB |
Output is correct |
65 |
Correct |
416 ms |
52276 KB |
Output is correct |
66 |
Correct |
368 ms |
34628 KB |
Output is correct |
67 |
Correct |
409 ms |
54896 KB |
Output is correct |
68 |
Correct |
5 ms |
9720 KB |
Output is correct |
69 |
Correct |
5 ms |
9716 KB |
Output is correct |
70 |
Correct |
5 ms |
9676 KB |
Output is correct |
71 |
Correct |
5 ms |
9676 KB |
Output is correct |
72 |
Correct |
5 ms |
9712 KB |
Output is correct |
73 |
Correct |
5 ms |
9676 KB |
Output is correct |
74 |
Correct |
5 ms |
9712 KB |
Output is correct |
75 |
Correct |
6 ms |
9648 KB |
Output is correct |
76 |
Correct |
6 ms |
9676 KB |
Output is correct |
77 |
Correct |
5 ms |
9676 KB |
Output is correct |
78 |
Correct |
5 ms |
9676 KB |
Output is correct |
79 |
Correct |
5 ms |
9676 KB |
Output is correct |
80 |
Correct |
5 ms |
9676 KB |
Output is correct |
81 |
Correct |
5 ms |
9676 KB |
Output is correct |
82 |
Correct |
5 ms |
9676 KB |
Output is correct |
83 |
Correct |
5 ms |
9676 KB |
Output is correct |