#include <bits/stdc++.h>
using namespace std;
const int MN=1e5+2;
int N;
set<int> fromgr[MN];
int togr[MN];
bool vis[MN];
int dpst[MN], dpew[MN];
void dfs(int u, int root) {
vis[u] = 1;
if(fromgr[u].empty()) {
dpst[u] = 1;
dpew[u] = 0;
return;
}
dpst[u] = 1e9;
dpew[u] = 0;
for(int v : fromgr[u]) {
if(v == root) continue;
dfs(v, root);
dpew[u] += dpst[v];
}
for(int v : fromgr[u]) {
if(v == root) continue;
dpst[u] = min(dpst[u], dpew[u] - dpst[v] + dpew[v] + 1);
}
if(dpst[u] == (int)1e9) dpst[u] = 1;
}
int solve(int u) {
vector<bool> seen(N, 0);
// find root
seen[u] = 1;
while(!seen[togr[u]]) {
u = togr[u];
seen[u] = 1;
}
// relationship
if(togr[u] != u && togr[togr[u]] == u) {
dfs(u, togr[u]);
dfs(togr[u], u);
return dpew[u] + dpew[togr[u]];
}
dfs(u, u);
int ans = min(dpst[u], dpew[u] + 1);
fromgr[togr[togr[u]]].erase(togr[u]);
dfs(u, u);
return min(ans, dpew[u] + dpew[togr[u]] + 1);
}
int main() {
ios::sync_with_stdio(0); cin.tie(0);
cin>>N;
if(N%2) {
cout<<"-1\n";
return 0;
}
unordered_map<string, int> id;
vector<string> pts;
for(int i=0; i<N; ++i) {
string a,b;
cin>>a>>b;
id[a] = i;
pts.emplace_back(b);
}
for(int i=0; i<N; ++i) {
togr[i] = id[pts[i]];
fromgr[id[pts[i]]].emplace(i);
}
int ans = 0;
for(int i=0; i<N; ++i) {
if(vis[i]) continue;
ans += solve(i);
}
// for(int i=0; i<N; ++i) cout<<dpst[i]<<' '<<dpew[i]<<'\n';
cout<<ans<<'\n';
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
6232 KB |
Output is correct |
2 |
Correct |
2 ms |
6240 KB |
Output is correct |
3 |
Correct |
1 ms |
6236 KB |
Output is correct |
4 |
Correct |
2 ms |
6236 KB |
Output is correct |
5 |
Correct |
2 ms |
6236 KB |
Output is correct |
6 |
Correct |
2 ms |
6232 KB |
Output is correct |
7 |
Correct |
2 ms |
6236 KB |
Output is correct |
8 |
Correct |
2 ms |
6236 KB |
Output is correct |
9 |
Correct |
3 ms |
6236 KB |
Output is correct |
10 |
Correct |
2 ms |
6236 KB |
Output is correct |
11 |
Correct |
2 ms |
6236 KB |
Output is correct |
12 |
Correct |
2 ms |
6236 KB |
Output is correct |
13 |
Correct |
2 ms |
6236 KB |
Output is correct |
14 |
Correct |
2 ms |
6236 KB |
Output is correct |
15 |
Correct |
2 ms |
6236 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
6236 KB |
Output is correct |
2 |
Correct |
2 ms |
6236 KB |
Output is correct |
3 |
Correct |
2 ms |
6232 KB |
Output is correct |
4 |
Correct |
90 ms |
30648 KB |
Output is correct |
5 |
Correct |
73 ms |
24504 KB |
Output is correct |
6 |
Correct |
131 ms |
32664 KB |
Output is correct |
7 |
Correct |
2 ms |
6236 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
74 ms |
21872 KB |
Output is correct |
2 |
Correct |
79 ms |
23580 KB |
Output is correct |
3 |
Correct |
73 ms |
22296 KB |
Output is correct |
4 |
Correct |
1 ms |
6236 KB |
Output is correct |
5 |
Correct |
86 ms |
29344 KB |
Output is correct |
6 |
Correct |
85 ms |
21684 KB |
Output is correct |
7 |
Correct |
73 ms |
22728 KB |
Output is correct |
8 |
Correct |
82 ms |
21812 KB |
Output is correct |
9 |
Correct |
86 ms |
21688 KB |
Output is correct |
10 |
Correct |
59 ms |
21688 KB |
Output is correct |
11 |
Correct |
2 ms |
6236 KB |
Output is correct |
12 |
Correct |
1 ms |
6236 KB |
Output is correct |
13 |
Correct |
2 ms |
6236 KB |
Output is correct |
14 |
Correct |
2 ms |
6236 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
6232 KB |
Output is correct |
2 |
Correct |
2 ms |
6240 KB |
Output is correct |
3 |
Correct |
1 ms |
6236 KB |
Output is correct |
4 |
Correct |
2 ms |
6236 KB |
Output is correct |
5 |
Correct |
2 ms |
6236 KB |
Output is correct |
6 |
Correct |
2 ms |
6232 KB |
Output is correct |
7 |
Correct |
2 ms |
6236 KB |
Output is correct |
8 |
Correct |
2 ms |
6236 KB |
Output is correct |
9 |
Correct |
3 ms |
6236 KB |
Output is correct |
10 |
Correct |
2 ms |
6236 KB |
Output is correct |
11 |
Correct |
2 ms |
6236 KB |
Output is correct |
12 |
Correct |
2 ms |
6236 KB |
Output is correct |
13 |
Correct |
2 ms |
6236 KB |
Output is correct |
14 |
Correct |
2 ms |
6236 KB |
Output is correct |
15 |
Correct |
2 ms |
6236 KB |
Output is correct |
16 |
Correct |
2 ms |
6236 KB |
Output is correct |
17 |
Correct |
2 ms |
6236 KB |
Output is correct |
18 |
Correct |
2 ms |
6232 KB |
Output is correct |
19 |
Correct |
90 ms |
30648 KB |
Output is correct |
20 |
Correct |
73 ms |
24504 KB |
Output is correct |
21 |
Correct |
131 ms |
32664 KB |
Output is correct |
22 |
Correct |
2 ms |
6236 KB |
Output is correct |
23 |
Correct |
74 ms |
21872 KB |
Output is correct |
24 |
Correct |
79 ms |
23580 KB |
Output is correct |
25 |
Correct |
73 ms |
22296 KB |
Output is correct |
26 |
Correct |
1 ms |
6236 KB |
Output is correct |
27 |
Correct |
86 ms |
29344 KB |
Output is correct |
28 |
Correct |
85 ms |
21684 KB |
Output is correct |
29 |
Correct |
73 ms |
22728 KB |
Output is correct |
30 |
Correct |
82 ms |
21812 KB |
Output is correct |
31 |
Correct |
86 ms |
21688 KB |
Output is correct |
32 |
Correct |
59 ms |
21688 KB |
Output is correct |
33 |
Correct |
2 ms |
6236 KB |
Output is correct |
34 |
Correct |
1 ms |
6236 KB |
Output is correct |
35 |
Correct |
2 ms |
6236 KB |
Output is correct |
36 |
Correct |
2 ms |
6236 KB |
Output is correct |
37 |
Correct |
87 ms |
23996 KB |
Output is correct |
38 |
Correct |
82 ms |
25868 KB |
Output is correct |
39 |
Correct |
74 ms |
24252 KB |
Output is correct |
40 |
Correct |
75 ms |
23988 KB |
Output is correct |
41 |
Correct |
74 ms |
24760 KB |
Output is correct |
42 |
Correct |
95 ms |
23988 KB |
Output is correct |
43 |
Correct |
69 ms |
23996 KB |
Output is correct |
44 |
Correct |
69 ms |
25020 KB |
Output is correct |
45 |
Correct |
73 ms |
24316 KB |
Output is correct |
46 |
Correct |
71 ms |
24276 KB |
Output is correct |
47 |
Correct |
73 ms |
23992 KB |
Output is correct |
48 |
Correct |
73 ms |
24028 KB |
Output is correct |
49 |
Correct |
76 ms |
26272 KB |
Output is correct |
50 |
Correct |
73 ms |
23992 KB |
Output is correct |
51 |
Correct |
2 ms |
6236 KB |
Output is correct |
52 |
Correct |
92 ms |
31108 KB |
Output is correct |
53 |
Correct |
95 ms |
23992 KB |
Output is correct |
54 |
Correct |
88 ms |
24024 KB |
Output is correct |
55 |
Correct |
75 ms |
23992 KB |
Output is correct |
56 |
Correct |
72 ms |
24768 KB |
Output is correct |
57 |
Correct |
60 ms |
24248 KB |
Output is correct |
58 |
Correct |
2 ms |
6236 KB |
Output is correct |
59 |
Correct |
2 ms |
6236 KB |
Output is correct |
60 |
Correct |
2 ms |
6264 KB |
Output is correct |
61 |
Correct |
2 ms |
6236 KB |
Output is correct |
62 |
Correct |
3 ms |
6236 KB |
Output is correct |
63 |
Correct |
2 ms |
6236 KB |
Output is correct |
64 |
Correct |
2 ms |
6236 KB |
Output is correct |
65 |
Correct |
88 ms |
30736 KB |
Output is correct |
66 |
Correct |
70 ms |
23900 KB |
Output is correct |
67 |
Correct |
90 ms |
32184 KB |
Output is correct |
68 |
Correct |
2 ms |
6236 KB |
Output is correct |
69 |
Correct |
2 ms |
6236 KB |
Output is correct |
70 |
Correct |
2 ms |
6236 KB |
Output is correct |
71 |
Correct |
2 ms |
6236 KB |
Output is correct |
72 |
Correct |
2 ms |
6236 KB |
Output is correct |
73 |
Correct |
2 ms |
6236 KB |
Output is correct |
74 |
Correct |
2 ms |
6236 KB |
Output is correct |
75 |
Correct |
2 ms |
6256 KB |
Output is correct |
76 |
Correct |
2 ms |
6236 KB |
Output is correct |
77 |
Correct |
2 ms |
6236 KB |
Output is correct |
78 |
Correct |
1 ms |
6236 KB |
Output is correct |
79 |
Correct |
3 ms |
6260 KB |
Output is correct |
80 |
Correct |
2 ms |
6488 KB |
Output is correct |
81 |
Correct |
2 ms |
6236 KB |
Output is correct |
82 |
Correct |
2 ms |
6236 KB |
Output is correct |
83 |
Correct |
2 ms |
6236 KB |
Output is correct |