#include <bits/stdc++.h>
using namespace std;
#define m_p make_pair
const int N = 100005;
int n;
pair<string, string> kk[N];
map<string, int> mp;
int h[N];
vector<int> a[N];
vector<vector<int> > cycles;
int c[N];
int s, f;
int p[N];
bool dfs0(int x)
{
c[x] = 1;
if (c[h[x]] == 1)
{
s = h[x];
f = x;
c[x] = 2;
return true;
}
if (c[h[x]] == 0)
{
p[h[x]] = x;
if (dfs0(h[x]))
{
c[x] = 2;
return true;
}
}
c[x] = 2;
return false;
}
int dp[N][2];
void dfs(int x)
{
for (int i = 0; i < a[x].size(); ++i)
{
int h = a[x][i];
if (c[h])
continue;
dfs(h);
dp[x][0] += (min(dp[h][0], dp[h][1]) + 1);
}
dp[x][1] = N;
for (int i = 0; i < a[x].size(); ++i)
{
int h = a[x][i];
if (c[h])
continue;
dp[x][0] -= (min(dp[h][0], dp[h][1]) + 1);
dp[x][1] = min(dp[x][1], dp[h][0] + dp[x][0]);
dp[x][0] += (min(dp[h][0], dp[h][1]) + 1);
}
}
int dp1[N][2];
int solv(const vector<int>& v)
{
if (v.size() == 2)
{
return min(dp[v[0]][0] + dp[v[1]][0],
dp[v[0]][1] + dp[v[1]][1] + 2);
}
dp1[v[0]][0] = dp[v[0]][0];
dp1[v[0]][1] = dp[v[0]][1];
for (int i = 1; i < v.size(); ++i)
{
dp1[v[i]][0] = min(dp1[v[i - 1]][0], dp1[v[i - 1]][1]) + 1 + dp[v[i]][0];
dp1[v[i]][1] = min(min(dp1[v[i - 1]][0], dp1[v[i - 1]][1]) + 1 + dp[v[i]][1],
dp1[v[i - 1]][0] + dp[v[i]][0]);
}
return min(dp1[v.back()][0], dp1[v.back()][1]) + 1;
}
int main()
{
ios_base::sync_with_stdio(false);
cin >> n;
for (int i = 1; i <= n; ++i)
{
cin >> kk[i].first >> kk[i].second;
mp[kk[i].first] = i;
}
if (n % 2 == 1)
{
cout << -1 << endl;
return 0;
}
for (int i = 1; i <= n; ++i)
{
h[i] = mp[kk[i].second];
a[mp[kk[i].second]].push_back(mp[kk[i].first]);
}
for (int i = 1; i <= n; ++i)
{
if (!c[i])
{
if (dfs0(i))
{
vector<int> v;
for (int x = f; x != s; x = p[x])
v.push_back(x);
v.push_back(s);
reverse(v.begin(), v.end());
cycles.push_back(v);
}
}
}
memset(c, 0, sizeof c);
for (int i = 0; i < cycles.size(); ++i)
{
for (int j = 0; j < cycles[i].size(); ++j)
{
int x = cycles[i][j];
c[x] = 1;
}
}
for (int x = 1; x <= n; ++x)
{
if (c[x])
dfs(x);
}
int ans = 0;
for (int i = 0; i < cycles.size(); ++i)
{
int yans = solv(cycles[i]);
int x = cycles[i].back();
cycles[i].pop_back();
reverse(cycles[i].begin(), cycles[i].end());
cycles[i].push_back(x);
reverse(cycles[i].begin(), cycles[i].end());
yans = min(yans, solv(cycles[i]));
ans += yans;
}
cout << ans << endl;
return 0;
}
Compilation message
polygon.cpp: In function 'void dfs(int)':
polygon.cpp:43:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
43 | for (int i = 0; i < a[x].size(); ++i)
| ~~^~~~~~~~~~~~~
polygon.cpp:52:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
52 | for (int i = 0; i < a[x].size(); ++i)
| ~~^~~~~~~~~~~~~
polygon.cpp: In function 'int solv(const std::vector<int>&)':
polygon.cpp:73:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
73 | for (int i = 1; i < v.size(); ++i)
| ~~^~~~~~~~~~
polygon.cpp: In function 'int main()':
polygon.cpp:117:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
117 | for (int i = 0; i < cycles.size(); ++i)
| ~~^~~~~~~~~~~~~~~
polygon.cpp:119:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
119 | for (int j = 0; j < cycles[i].size(); ++j)
| ~~^~~~~~~~~~~~~~~~~~
polygon.cpp:131:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
131 | for (int i = 0; i < cycles.size(); ++i)
| ~~^~~~~~~~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
5 ms |
9292 KB |
Output is correct |
2 |
Correct |
5 ms |
9292 KB |
Output is correct |
3 |
Correct |
5 ms |
9292 KB |
Output is correct |
4 |
Correct |
5 ms |
9268 KB |
Output is correct |
5 |
Correct |
4 ms |
8932 KB |
Output is correct |
6 |
Correct |
4 ms |
8908 KB |
Output is correct |
7 |
Correct |
5 ms |
9292 KB |
Output is correct |
8 |
Correct |
5 ms |
9292 KB |
Output is correct |
9 |
Correct |
5 ms |
9292 KB |
Output is correct |
10 |
Correct |
5 ms |
9320 KB |
Output is correct |
11 |
Correct |
5 ms |
9292 KB |
Output is correct |
12 |
Correct |
5 ms |
9316 KB |
Output is correct |
13 |
Correct |
5 ms |
9292 KB |
Output is correct |
14 |
Correct |
5 ms |
9292 KB |
Output is correct |
15 |
Correct |
5 ms |
9292 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
5 ms |
9292 KB |
Output is correct |
2 |
Correct |
5 ms |
9292 KB |
Output is correct |
3 |
Correct |
7 ms |
9292 KB |
Output is correct |
4 |
Correct |
198 ms |
27832 KB |
Output is correct |
5 |
Correct |
238 ms |
25900 KB |
Output is correct |
6 |
Correct |
224 ms |
28456 KB |
Output is correct |
7 |
Correct |
77 ms |
18880 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
195 ms |
23960 KB |
Output is correct |
2 |
Correct |
204 ms |
24772 KB |
Output is correct |
3 |
Correct |
168 ms |
29824 KB |
Output is correct |
4 |
Correct |
68 ms |
18884 KB |
Output is correct |
5 |
Correct |
202 ms |
29772 KB |
Output is correct |
6 |
Correct |
197 ms |
22444 KB |
Output is correct |
7 |
Correct |
207 ms |
23344 KB |
Output is correct |
8 |
Correct |
182 ms |
26336 KB |
Output is correct |
9 |
Correct |
180 ms |
21960 KB |
Output is correct |
10 |
Correct |
146 ms |
21004 KB |
Output is correct |
11 |
Correct |
6 ms |
9292 KB |
Output is correct |
12 |
Correct |
4 ms |
9320 KB |
Output is correct |
13 |
Correct |
5 ms |
9320 KB |
Output is correct |
14 |
Correct |
5 ms |
9320 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
5 ms |
9292 KB |
Output is correct |
2 |
Correct |
5 ms |
9292 KB |
Output is correct |
3 |
Correct |
5 ms |
9292 KB |
Output is correct |
4 |
Correct |
5 ms |
9268 KB |
Output is correct |
5 |
Correct |
4 ms |
8932 KB |
Output is correct |
6 |
Correct |
4 ms |
8908 KB |
Output is correct |
7 |
Correct |
5 ms |
9292 KB |
Output is correct |
8 |
Correct |
5 ms |
9292 KB |
Output is correct |
9 |
Correct |
5 ms |
9292 KB |
Output is correct |
10 |
Correct |
5 ms |
9320 KB |
Output is correct |
11 |
Correct |
5 ms |
9292 KB |
Output is correct |
12 |
Correct |
5 ms |
9316 KB |
Output is correct |
13 |
Correct |
5 ms |
9292 KB |
Output is correct |
14 |
Correct |
5 ms |
9292 KB |
Output is correct |
15 |
Correct |
5 ms |
9292 KB |
Output is correct |
16 |
Correct |
5 ms |
9292 KB |
Output is correct |
17 |
Correct |
5 ms |
9292 KB |
Output is correct |
18 |
Correct |
7 ms |
9292 KB |
Output is correct |
19 |
Correct |
198 ms |
27832 KB |
Output is correct |
20 |
Correct |
238 ms |
25900 KB |
Output is correct |
21 |
Correct |
224 ms |
28456 KB |
Output is correct |
22 |
Correct |
77 ms |
18880 KB |
Output is correct |
23 |
Correct |
195 ms |
23960 KB |
Output is correct |
24 |
Correct |
204 ms |
24772 KB |
Output is correct |
25 |
Correct |
168 ms |
29824 KB |
Output is correct |
26 |
Correct |
68 ms |
18884 KB |
Output is correct |
27 |
Correct |
202 ms |
29772 KB |
Output is correct |
28 |
Correct |
197 ms |
22444 KB |
Output is correct |
29 |
Correct |
207 ms |
23344 KB |
Output is correct |
30 |
Correct |
182 ms |
26336 KB |
Output is correct |
31 |
Correct |
180 ms |
21960 KB |
Output is correct |
32 |
Correct |
146 ms |
21004 KB |
Output is correct |
33 |
Correct |
6 ms |
9292 KB |
Output is correct |
34 |
Correct |
4 ms |
9320 KB |
Output is correct |
35 |
Correct |
5 ms |
9320 KB |
Output is correct |
36 |
Correct |
5 ms |
9320 KB |
Output is correct |
37 |
Correct |
193 ms |
24384 KB |
Output is correct |
38 |
Correct |
199 ms |
24044 KB |
Output is correct |
39 |
Correct |
201 ms |
23804 KB |
Output is correct |
40 |
Correct |
196 ms |
22680 KB |
Output is correct |
41 |
Correct |
193 ms |
22772 KB |
Output is correct |
42 |
Correct |
214 ms |
23364 KB |
Output is correct |
43 |
Correct |
195 ms |
23488 KB |
Output is correct |
44 |
Correct |
197 ms |
23492 KB |
Output is correct |
45 |
Correct |
208 ms |
23568 KB |
Output is correct |
46 |
Correct |
201 ms |
23492 KB |
Output is correct |
47 |
Correct |
186 ms |
22728 KB |
Output is correct |
48 |
Correct |
206 ms |
24132 KB |
Output is correct |
49 |
Correct |
201 ms |
24900 KB |
Output is correct |
50 |
Correct |
172 ms |
29796 KB |
Output is correct |
51 |
Correct |
74 ms |
18808 KB |
Output is correct |
52 |
Correct |
218 ms |
29764 KB |
Output is correct |
53 |
Correct |
194 ms |
22472 KB |
Output is correct |
54 |
Correct |
206 ms |
23248 KB |
Output is correct |
55 |
Correct |
198 ms |
26264 KB |
Output is correct |
56 |
Correct |
190 ms |
21912 KB |
Output is correct |
57 |
Correct |
142 ms |
20964 KB |
Output is correct |
58 |
Correct |
5 ms |
9292 KB |
Output is correct |
59 |
Correct |
5 ms |
9320 KB |
Output is correct |
60 |
Correct |
5 ms |
9292 KB |
Output is correct |
61 |
Correct |
5 ms |
9320 KB |
Output is correct |
62 |
Correct |
5 ms |
9292 KB |
Output is correct |
63 |
Correct |
5 ms |
9292 KB |
Output is correct |
64 |
Correct |
5 ms |
9292 KB |
Output is correct |
65 |
Correct |
202 ms |
27976 KB |
Output is correct |
66 |
Correct |
196 ms |
25896 KB |
Output is correct |
67 |
Correct |
197 ms |
28392 KB |
Output is correct |
68 |
Correct |
76 ms |
18824 KB |
Output is correct |
69 |
Correct |
6 ms |
9292 KB |
Output is correct |
70 |
Correct |
5 ms |
9320 KB |
Output is correct |
71 |
Correct |
4 ms |
9292 KB |
Output is correct |
72 |
Correct |
5 ms |
9292 KB |
Output is correct |
73 |
Correct |
4 ms |
8908 KB |
Output is correct |
74 |
Correct |
4 ms |
8908 KB |
Output is correct |
75 |
Correct |
5 ms |
9292 KB |
Output is correct |
76 |
Correct |
6 ms |
9316 KB |
Output is correct |
77 |
Correct |
5 ms |
9292 KB |
Output is correct |
78 |
Correct |
5 ms |
9316 KB |
Output is correct |
79 |
Correct |
5 ms |
9292 KB |
Output is correct |
80 |
Correct |
5 ms |
9292 KB |
Output is correct |
81 |
Correct |
5 ms |
9292 KB |
Output is correct |
82 |
Correct |
5 ms |
9292 KB |
Output is correct |
83 |
Correct |
5 ms |
9292 KB |
Output is correct |