#include <bits/stdc++.h>
using namespace std;
const int MAXN = 1e5 + 25;
int p[MAXN], n, deg[MAXN];
map <string, int> d;
bool vis[MAXN];
queue <int> o;
int main () {
ios::sync_with_stdio(0); cin.tie(0);
cin >> n;
for (int i = 0; i < n; i++) {
string s, t;
cin >> s >> t;
if (!d.count(s)) d[s] = (int)d.size();
if (!d.count(t)) d[t] = (int)d.size();
p[d[s]] = d[t];
deg[d[t]]++;
}
if (n & 1) {
cout << "-1\n";
return 0;
}
int ans = 0;
for (int i = 0; i < n; i++) if (deg[i] == 0) o.push(i);
while (!o.empty()) {
auto k = o.front(); o.pop();
if (deg[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;
deg[k]++; deg[p[k]]--;
ans++;
continue;
}
ans++;
deg[p[p[k]]]--;
if (deg[p[p[k]]] == 0) {
o.push(p[p[k]]);
}
p[p[k]] = k; deg[k]++;
}
for (int i = 0; i < n; i++) {
if (deg[i] == 0) {
ans++;
deg[i] = 2;
deg[p[i]]--;
}
}
for (int i = 0; i < n; i++) {
if (deg[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) + (z & 1);
}
}
cout << ans << '\n';
}
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
344 KB |
Output is correct |
| 2 |
Correct |
0 ms |
348 KB |
Output is correct |
| 3 |
Correct |
0 ms |
348 KB |
Output is correct |
| 4 |
Correct |
0 ms |
348 KB |
Output is correct |
| 5 |
Correct |
0 ms |
348 KB |
Output is correct |
| 6 |
Correct |
0 ms |
468 KB |
Output is correct |
| 7 |
Correct |
0 ms |
348 KB |
Output is correct |
| 8 |
Correct |
0 ms |
348 KB |
Output is correct |
| 9 |
Correct |
1 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 |
1 ms |
348 KB |
Output is correct |
| 14 |
Correct |
0 ms |
348 KB |
Output is correct |
| 15 |
Correct |
1 ms |
348 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
348 KB |
Output is correct |
| 2 |
Correct |
0 ms |
348 KB |
Output is correct |
| 3 |
Correct |
1 ms |
504 KB |
Output is correct |
| 4 |
Correct |
154 ms |
12104 KB |
Output is correct |
| 5 |
Correct |
144 ms |
11228 KB |
Output is correct |
| 6 |
Correct |
143 ms |
11832 KB |
Output is correct |
| 7 |
Correct |
160 ms |
11000 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
162 ms |
11232 KB |
Output is correct |
| 2 |
Correct |
161 ms |
11320 KB |
Output is correct |
| 3 |
Correct |
128 ms |
11188 KB |
Output is correct |
| 4 |
Correct |
161 ms |
11332 KB |
Output is correct |
| 5 |
Correct |
149 ms |
11092 KB |
Output is correct |
| 6 |
Correct |
142 ms |
11368 KB |
Output is correct |
| 7 |
Correct |
141 ms |
11348 KB |
Output is correct |
| 8 |
Correct |
139 ms |
11248 KB |
Output is correct |
| 9 |
Correct |
139 ms |
11600 KB |
Output is correct |
| 10 |
Correct |
103 ms |
11600 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 |
1 ms |
348 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
344 KB |
Output is correct |
| 2 |
Correct |
0 ms |
348 KB |
Output is correct |
| 3 |
Correct |
0 ms |
348 KB |
Output is correct |
| 4 |
Correct |
0 ms |
348 KB |
Output is correct |
| 5 |
Correct |
0 ms |
348 KB |
Output is correct |
| 6 |
Correct |
0 ms |
468 KB |
Output is correct |
| 7 |
Correct |
0 ms |
348 KB |
Output is correct |
| 8 |
Correct |
0 ms |
348 KB |
Output is correct |
| 9 |
Correct |
1 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 |
1 ms |
348 KB |
Output is correct |
| 14 |
Correct |
0 ms |
348 KB |
Output is correct |
| 15 |
Correct |
1 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 |
1 ms |
504 KB |
Output is correct |
| 19 |
Correct |
154 ms |
12104 KB |
Output is correct |
| 20 |
Correct |
144 ms |
11228 KB |
Output is correct |
| 21 |
Correct |
143 ms |
11832 KB |
Output is correct |
| 22 |
Correct |
160 ms |
11000 KB |
Output is correct |
| 23 |
Correct |
162 ms |
11232 KB |
Output is correct |
| 24 |
Correct |
161 ms |
11320 KB |
Output is correct |
| 25 |
Correct |
128 ms |
11188 KB |
Output is correct |
| 26 |
Correct |
161 ms |
11332 KB |
Output is correct |
| 27 |
Correct |
149 ms |
11092 KB |
Output is correct |
| 28 |
Correct |
142 ms |
11368 KB |
Output is correct |
| 29 |
Correct |
141 ms |
11348 KB |
Output is correct |
| 30 |
Correct |
139 ms |
11248 KB |
Output is correct |
| 31 |
Correct |
139 ms |
11600 KB |
Output is correct |
| 32 |
Correct |
103 ms |
11600 KB |
Output is correct |
| 33 |
Correct |
0 ms |
348 KB |
Output is correct |
| 34 |
Correct |
0 ms |
348 KB |
Output is correct |
| 35 |
Correct |
0 ms |
348 KB |
Output is correct |
| 36 |
Correct |
1 ms |
348 KB |
Output is correct |
| 37 |
Correct |
147 ms |
11348 KB |
Output is correct |
| 38 |
Correct |
143 ms |
11376 KB |
Output is correct |
| 39 |
Correct |
143 ms |
11348 KB |
Output is correct |
| 40 |
Correct |
146 ms |
11692 KB |
Output is correct |
| 41 |
Correct |
143 ms |
11344 KB |
Output is correct |
| 42 |
Correct |
145 ms |
11348 KB |
Output is correct |
| 43 |
Correct |
169 ms |
11348 KB |
Output is correct |
| 44 |
Correct |
145 ms |
11348 KB |
Output is correct |
| 45 |
Correct |
143 ms |
11344 KB |
Output is correct |
| 46 |
Correct |
145 ms |
11344 KB |
Output is correct |
| 47 |
Correct |
138 ms |
11364 KB |
Output is correct |
| 48 |
Correct |
144 ms |
11348 KB |
Output is correct |
| 49 |
Correct |
145 ms |
11344 KB |
Output is correct |
| 50 |
Correct |
129 ms |
11088 KB |
Output is correct |
| 51 |
Correct |
139 ms |
11204 KB |
Output is correct |
| 52 |
Correct |
152 ms |
11216 KB |
Output is correct |
| 53 |
Correct |
149 ms |
11344 KB |
Output is correct |
| 54 |
Correct |
143 ms |
11476 KB |
Output is correct |
| 55 |
Correct |
144 ms |
11340 KB |
Output is correct |
| 56 |
Correct |
148 ms |
11428 KB |
Output is correct |
| 57 |
Correct |
102 ms |
11604 KB |
Output is correct |
| 58 |
Correct |
0 ms |
348 KB |
Output is correct |
| 59 |
Correct |
0 ms |
348 KB |
Output is correct |
| 60 |
Correct |
0 ms |
348 KB |
Output is correct |
| 61 |
Correct |
0 ms |
348 KB |
Output is correct |
| 62 |
Correct |
1 ms |
348 KB |
Output is correct |
| 63 |
Correct |
0 ms |
348 KB |
Output is correct |
| 64 |
Correct |
0 ms |
348 KB |
Output is correct |
| 65 |
Correct |
150 ms |
11812 KB |
Output is correct |
| 66 |
Correct |
143 ms |
11092 KB |
Output is correct |
| 67 |
Correct |
158 ms |
12196 KB |
Output is correct |
| 68 |
Correct |
184 ms |
11024 KB |
Output is correct |
| 69 |
Correct |
1 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 |
0 ms |
344 KB |
Output is correct |
| 77 |
Correct |
1 ms |
348 KB |
Output is correct |
| 78 |
Correct |
0 ms |
348 KB |
Output is correct |
| 79 |
Correct |
1 ms |
396 KB |
Output is correct |
| 80 |
Correct |
0 ms |
472 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 |
