#include <bits/stdc++.h>
using namespace std;
int p[100025], n, grad[100025];
map<string, int> nume;
bool vis[100025];
queue<int> q;
int main ()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cin >> n;
for(int i = 0; i < n; i ++)
{
string s, t;
cin >> s >> t;
if(!nume.count(s))
nume[s] = (int)nume.size();
if(!nume.count(t))
nume[t] = (int)nume.size();
p[nume[s]] = nume[t];
grad[nume[t]] ++;
}
if(n % 2 == 1)
{
cout << -1;
return 0;
}
int ans = 0;
for(int i = 0; i < n; i ++)
if (grad[i] == 0)
q.push(i);
while (!q.empty())
{
auto k = q.front();
q.pop();
if(grad[k] != 0)
continue;
if(p[p[k]] != p[k] && p[p[p[k]]] == p[k])
continue;
if(p[p[k]] == p[k])
{
p[p[k]] = k;
grad[k] ++;
grad[p[k]] --;
ans ++;
continue;
}
ans ++;
grad[p[p[k]]] --;
if(grad[p[p[k]]] == 0)
q.push(p[p[k]]);
p[p[k]] = k;
grad[k] ++;
}
for(int i = 0; i < n; i ++)
if(grad[i] == 0)
{
ans++;
grad[i] = 2;
grad[p[i]] --;
}
for(int i = 0; i < n; i ++)
if(grad[i] == 1 && !vis[i])
{
vector<int> t = {i};
vis[i] = 1;
int u = p[i];
while(u != i)
{
t.push_back(u);
vis[u] = 1;
u = p[u];
}
if(t.size() == 2)
continue;
int z = t.size();
ans += (z + 1) / 2;
}
cout << ans;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
344 KB |
Output is correct |
2 |
Correct |
0 ms |
348 KB |
Output is correct |
3 |
Correct |
0 ms |
344 KB |
Output is correct |
4 |
Correct |
0 ms |
344 KB |
Output is correct |
5 |
Correct |
0 ms |
348 KB |
Output is correct |
6 |
Correct |
0 ms |
348 KB |
Output is correct |
7 |
Correct |
0 ms |
348 KB |
Output is correct |
8 |
Correct |
0 ms |
348 KB |
Output is correct |
9 |
Correct |
0 ms |
348 KB |
Output is correct |
10 |
Correct |
0 ms |
348 KB |
Output is correct |
11 |
Correct |
0 ms |
348 KB |
Output is correct |
12 |
Correct |
0 ms |
348 KB |
Output is correct |
13 |
Correct |
0 ms |
348 KB |
Output is correct |
14 |
Correct |
0 ms |
348 KB |
Output is correct |
15 |
Correct |
0 ms |
348 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
348 KB |
Output is correct |
2 |
Correct |
0 ms |
348 KB |
Output is correct |
3 |
Correct |
0 ms |
348 KB |
Output is correct |
4 |
Correct |
148 ms |
11928 KB |
Output is correct |
5 |
Correct |
148 ms |
11240 KB |
Output is correct |
6 |
Correct |
147 ms |
11712 KB |
Output is correct |
7 |
Correct |
145 ms |
11088 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
153 ms |
11388 KB |
Output is correct |
2 |
Correct |
147 ms |
11244 KB |
Output is correct |
3 |
Correct |
136 ms |
11084 KB |
Output is correct |
4 |
Correct |
149 ms |
11024 KB |
Output is correct |
5 |
Correct |
156 ms |
11224 KB |
Output is correct |
6 |
Correct |
143 ms |
11356 KB |
Output is correct |
7 |
Correct |
148 ms |
11348 KB |
Output is correct |
8 |
Correct |
152 ms |
11348 KB |
Output is correct |
9 |
Correct |
147 ms |
11600 KB |
Output is correct |
10 |
Correct |
107 ms |
11600 KB |
Output is correct |
11 |
Correct |
0 ms |
468 KB |
Output is correct |
12 |
Correct |
0 ms |
348 KB |
Output is correct |
13 |
Correct |
0 ms |
348 KB |
Output is correct |
14 |
Correct |
0 ms |
348 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
344 KB |
Output is correct |
2 |
Correct |
0 ms |
348 KB |
Output is correct |
3 |
Correct |
0 ms |
344 KB |
Output is correct |
4 |
Correct |
0 ms |
344 KB |
Output is correct |
5 |
Correct |
0 ms |
348 KB |
Output is correct |
6 |
Correct |
0 ms |
348 KB |
Output is correct |
7 |
Correct |
0 ms |
348 KB |
Output is correct |
8 |
Correct |
0 ms |
348 KB |
Output is correct |
9 |
Correct |
0 ms |
348 KB |
Output is correct |
10 |
Correct |
0 ms |
348 KB |
Output is correct |
11 |
Correct |
0 ms |
348 KB |
Output is correct |
12 |
Correct |
0 ms |
348 KB |
Output is correct |
13 |
Correct |
0 ms |
348 KB |
Output is correct |
14 |
Correct |
0 ms |
348 KB |
Output is correct |
15 |
Correct |
0 ms |
348 KB |
Output is correct |
16 |
Correct |
0 ms |
348 KB |
Output is correct |
17 |
Correct |
0 ms |
348 KB |
Output is correct |
18 |
Correct |
0 ms |
348 KB |
Output is correct |
19 |
Correct |
148 ms |
11928 KB |
Output is correct |
20 |
Correct |
148 ms |
11240 KB |
Output is correct |
21 |
Correct |
147 ms |
11712 KB |
Output is correct |
22 |
Correct |
145 ms |
11088 KB |
Output is correct |
23 |
Correct |
153 ms |
11388 KB |
Output is correct |
24 |
Correct |
147 ms |
11244 KB |
Output is correct |
25 |
Correct |
136 ms |
11084 KB |
Output is correct |
26 |
Correct |
149 ms |
11024 KB |
Output is correct |
27 |
Correct |
156 ms |
11224 KB |
Output is correct |
28 |
Correct |
143 ms |
11356 KB |
Output is correct |
29 |
Correct |
148 ms |
11348 KB |
Output is correct |
30 |
Correct |
152 ms |
11348 KB |
Output is correct |
31 |
Correct |
147 ms |
11600 KB |
Output is correct |
32 |
Correct |
107 ms |
11600 KB |
Output is correct |
33 |
Correct |
0 ms |
468 KB |
Output is correct |
34 |
Correct |
0 ms |
348 KB |
Output is correct |
35 |
Correct |
0 ms |
348 KB |
Output is correct |
36 |
Correct |
0 ms |
348 KB |
Output is correct |
37 |
Correct |
151 ms |
11196 KB |
Output is correct |
38 |
Correct |
147 ms |
11472 KB |
Output is correct |
39 |
Correct |
153 ms |
11304 KB |
Output is correct |
40 |
Correct |
151 ms |
11348 KB |
Output is correct |
41 |
Correct |
150 ms |
11344 KB |
Output is correct |
42 |
Correct |
144 ms |
11348 KB |
Output is correct |
43 |
Correct |
151 ms |
11344 KB |
Output is correct |
44 |
Correct |
144 ms |
11352 KB |
Output is correct |
45 |
Correct |
149 ms |
11348 KB |
Output is correct |
46 |
Correct |
149 ms |
11348 KB |
Output is correct |
47 |
Correct |
141 ms |
11600 KB |
Output is correct |
48 |
Correct |
144 ms |
11344 KB |
Output is correct |
49 |
Correct |
147 ms |
11248 KB |
Output is correct |
50 |
Correct |
131 ms |
11092 KB |
Output is correct |
51 |
Correct |
141 ms |
11088 KB |
Output is correct |
52 |
Correct |
146 ms |
11092 KB |
Output is correct |
53 |
Correct |
147 ms |
11348 KB |
Output is correct |
54 |
Correct |
146 ms |
11412 KB |
Output is correct |
55 |
Correct |
136 ms |
11368 KB |
Output is correct |
56 |
Correct |
135 ms |
11600 KB |
Output is correct |
57 |
Correct |
106 ms |
11464 KB |
Output is correct |
58 |
Correct |
0 ms |
348 KB |
Output is correct |
59 |
Correct |
1 ms |
348 KB |
Output is correct |
60 |
Correct |
1 ms |
600 KB |
Output is correct |
61 |
Correct |
1 ms |
348 KB |
Output is correct |
62 |
Correct |
0 ms |
348 KB |
Output is correct |
63 |
Correct |
0 ms |
428 KB |
Output is correct |
64 |
Correct |
0 ms |
348 KB |
Output is correct |
65 |
Correct |
147 ms |
11852 KB |
Output is correct |
66 |
Correct |
144 ms |
11088 KB |
Output is correct |
67 |
Correct |
150 ms |
11732 KB |
Output is correct |
68 |
Correct |
145 ms |
11092 KB |
Output is correct |
69 |
Correct |
0 ms |
348 KB |
Output is correct |
70 |
Correct |
0 ms |
348 KB |
Output is correct |
71 |
Correct |
0 ms |
348 KB |
Output is correct |
72 |
Correct |
0 ms |
348 KB |
Output is correct |
73 |
Correct |
0 ms |
348 KB |
Output is correct |
74 |
Correct |
0 ms |
348 KB |
Output is correct |
75 |
Correct |
0 ms |
348 KB |
Output is correct |
76 |
Correct |
1 ms |
344 KB |
Output is correct |
77 |
Correct |
0 ms |
348 KB |
Output is correct |
78 |
Correct |
0 ms |
348 KB |
Output is correct |
79 |
Correct |
0 ms |
348 KB |
Output is correct |
80 |
Correct |
0 ms |
348 KB |
Output is correct |
81 |
Correct |
0 ms |
348 KB |
Output is correct |
82 |
Correct |
0 ms |
348 KB |
Output is correct |
83 |
Correct |
0 ms |
348 KB |
Output is correct |