#include<bits/stdc++.h>
#define int long long
using namespace std;
const int maxn = 1e5 + 5;
int n, ans;
map<string,int> mp;
set<int> s;
queue<int> q;
int deg[maxn], nxt[maxn], nxt_two[maxn], mark[maxn];
signed main()
{
ios_base::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
// freopen("test.inp", "r", stdin);
// freopen("test.out", "w", stdout);
cin >> n;
for (int i = 1; i <= n; i++)
{
string u, v;
cin >> u >> v;
if (!mp.count(u)) mp[u] = mp.size() + 1;
if (!mp.count(v)) mp[v] = mp.size() + 1;
nxt[mp[u]] = mp[v];
deg[mp[v]]++;
}
if (mp.size() & 1) return cout << -1, 0;
n = mp.size();
for (int i = 1; i <= n; i++)
nxt_two[i] = nxt[nxt[i]],
s.emplace(i),
mark[i] = 1;
int cnt = n;
for (int i = 1; i <= n; i++)
if (mark[i] && nxt_two[i] == i && nxt[i] != i)
{
mark[i] = mark[nxt[i]] = 0;
s.erase(i); s.erase(nxt[i]);
cnt -= 2;
}
for (int i = 1; i <= n; i++)
if (mark[i] && deg[i] == 0)
q.emplace(i);
while (cnt)
{
if (q.empty()) q.emplace(*s.begin());
int u = q.front();
q.pop();
mark[u] = 0;
s.erase(u);
ans++;
cnt--;
if (mark[nxt[u]])
{
s.erase(nxt[u]);
cnt--;
mark[nxt[u]] = 0;
deg[nxt_two[u]]--;
if (mark[nxt_two[u]] && deg[nxt_two[u]] == 0)
q.emplace(nxt_two[u]);
}
}
cout << ans;
}
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
1 ms |
2392 KB |
Output is correct |
| 2 |
Correct |
1 ms |
2396 KB |
Output is correct |
| 3 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 4 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 5 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 6 |
Correct |
1 ms |
2396 KB |
Output is correct |
| 7 |
Correct |
1 ms |
2396 KB |
Output is correct |
| 8 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 9 |
Correct |
1 ms |
2396 KB |
Output is correct |
| 10 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 11 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 12 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 13 |
Correct |
1 ms |
2396 KB |
Output is correct |
| 14 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 15 |
Correct |
0 ms |
2396 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
1 ms |
2396 KB |
Output is correct |
| 2 |
Correct |
1 ms |
2396 KB |
Output is correct |
| 3 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 4 |
Correct |
183 ms |
15952 KB |
Output is correct |
| 5 |
Correct |
192 ms |
15956 KB |
Output is correct |
| 6 |
Correct |
181 ms |
15848 KB |
Output is correct |
| 7 |
Correct |
138 ms |
13140 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
173 ms |
16180 KB |
Output is correct |
| 2 |
Correct |
169 ms |
16212 KB |
Output is correct |
| 3 |
Correct |
162 ms |
15952 KB |
Output is correct |
| 4 |
Correct |
142 ms |
13288 KB |
Output is correct |
| 5 |
Correct |
204 ms |
15952 KB |
Output is correct |
| 6 |
Correct |
169 ms |
16464 KB |
Output is correct |
| 7 |
Correct |
163 ms |
16468 KB |
Output is correct |
| 8 |
Correct |
157 ms |
16208 KB |
Output is correct |
| 9 |
Correct |
155 ms |
16496 KB |
Output is correct |
| 10 |
Correct |
125 ms |
15952 KB |
Output is correct |
| 11 |
Correct |
1 ms |
2392 KB |
Output is correct |
| 12 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 13 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 14 |
Correct |
1 ms |
2396 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
1 ms |
2392 KB |
Output is correct |
| 2 |
Correct |
1 ms |
2396 KB |
Output is correct |
| 3 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 4 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 5 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 6 |
Correct |
1 ms |
2396 KB |
Output is correct |
| 7 |
Correct |
1 ms |
2396 KB |
Output is correct |
| 8 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 9 |
Correct |
1 ms |
2396 KB |
Output is correct |
| 10 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 11 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 12 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 13 |
Correct |
1 ms |
2396 KB |
Output is correct |
| 14 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 15 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 16 |
Correct |
1 ms |
2396 KB |
Output is correct |
| 17 |
Correct |
1 ms |
2396 KB |
Output is correct |
| 18 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 19 |
Correct |
183 ms |
15952 KB |
Output is correct |
| 20 |
Correct |
192 ms |
15956 KB |
Output is correct |
| 21 |
Correct |
181 ms |
15848 KB |
Output is correct |
| 22 |
Correct |
138 ms |
13140 KB |
Output is correct |
| 23 |
Correct |
173 ms |
16180 KB |
Output is correct |
| 24 |
Correct |
169 ms |
16212 KB |
Output is correct |
| 25 |
Correct |
162 ms |
15952 KB |
Output is correct |
| 26 |
Correct |
142 ms |
13288 KB |
Output is correct |
| 27 |
Correct |
204 ms |
15952 KB |
Output is correct |
| 28 |
Correct |
169 ms |
16464 KB |
Output is correct |
| 29 |
Correct |
163 ms |
16468 KB |
Output is correct |
| 30 |
Correct |
157 ms |
16208 KB |
Output is correct |
| 31 |
Correct |
155 ms |
16496 KB |
Output is correct |
| 32 |
Correct |
125 ms |
15952 KB |
Output is correct |
| 33 |
Correct |
1 ms |
2392 KB |
Output is correct |
| 34 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 35 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 36 |
Correct |
1 ms |
2396 KB |
Output is correct |
| 37 |
Correct |
189 ms |
15956 KB |
Output is correct |
| 38 |
Correct |
184 ms |
16464 KB |
Output is correct |
| 39 |
Correct |
177 ms |
16464 KB |
Output is correct |
| 40 |
Correct |
169 ms |
16464 KB |
Output is correct |
| 41 |
Correct |
182 ms |
16468 KB |
Output is correct |
| 42 |
Correct |
183 ms |
16212 KB |
Output is correct |
| 43 |
Correct |
203 ms |
16196 KB |
Output is correct |
| 44 |
Correct |
182 ms |
16212 KB |
Output is correct |
| 45 |
Correct |
211 ms |
16212 KB |
Output is correct |
| 46 |
Correct |
181 ms |
16208 KB |
Output is correct |
| 47 |
Correct |
187 ms |
16468 KB |
Output is correct |
| 48 |
Correct |
192 ms |
16260 KB |
Output is correct |
| 49 |
Correct |
185 ms |
16212 KB |
Output is correct |
| 50 |
Correct |
150 ms |
15956 KB |
Output is correct |
| 51 |
Correct |
147 ms |
13176 KB |
Output is correct |
| 52 |
Correct |
182 ms |
15892 KB |
Output is correct |
| 53 |
Correct |
174 ms |
16336 KB |
Output is correct |
| 54 |
Correct |
179 ms |
16464 KB |
Output is correct |
| 55 |
Correct |
167 ms |
16400 KB |
Output is correct |
| 56 |
Correct |
163 ms |
16464 KB |
Output is correct |
| 57 |
Correct |
119 ms |
15956 KB |
Output is correct |
| 58 |
Correct |
1 ms |
2396 KB |
Output is correct |
| 59 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 60 |
Correct |
1 ms |
2396 KB |
Output is correct |
| 61 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 62 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 63 |
Correct |
1 ms |
2396 KB |
Output is correct |
| 64 |
Correct |
1 ms |
2396 KB |
Output is correct |
| 65 |
Correct |
183 ms |
15896 KB |
Output is correct |
| 66 |
Correct |
180 ms |
15912 KB |
Output is correct |
| 67 |
Correct |
187 ms |
16040 KB |
Output is correct |
| 68 |
Correct |
144 ms |
13332 KB |
Output is correct |
| 69 |
Correct |
1 ms |
2392 KB |
Output is correct |
| 70 |
Correct |
1 ms |
2396 KB |
Output is correct |
| 71 |
Correct |
1 ms |
2396 KB |
Output is correct |
| 72 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 73 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 74 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 75 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 76 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 77 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 78 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 79 |
Correct |
1 ms |
2396 KB |
Output is correct |
| 80 |
Correct |
1 ms |
2392 KB |
Output is correct |
| 81 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 82 |
Correct |
0 ms |
2396 KB |
Output is correct |
| 83 |
Correct |
1 ms |
2392 KB |
Output is correct |
