#include <bits/stdc++.h>
#define ll long long
using namespace std;
const int maxn = 2e5 + 3;
map<string, int> mpp;
int nxt[maxn];
bool mark[maxn];
vector<int> O;
void dfs (int v) {
mark[v] = true;
if (!mark[nxt[v]])
dfs(nxt[v]);
O.push_back(v);
}
int main() {
ios::sync_with_stdio(false);cin.tie(0);
int m, count = 0;
cin >> m;
for (int i = 1; i <= m; i++) {
string s, ss;
cin >> s >> ss;
if (!mpp.count(s))
mpp[s] = ++count;
if (!mpp.count(ss))
mpp[ss] = ++count;
nxt[mpp[s]] = mpp[ss];
}
if (count & 1)
return cout << "-1\n", 0;
int ans = 0;
for (int i = 1; i <= count; i++)
if (!mark[i]) dfs(i);
reverse(O.begin(), O.end());
memset(mark, 0, sizeof mark);
for (int i: O) {
if (mark[i])
continue;
if (nxt[i] == i) {
++ans;
mark[i] = true;
continue;
}
if (nxt[nxt[i]] == i) {
mark[i] = true;
mark[nxt[i]] = true;
}
}
for (int i: O) {
if (mark[i])
continue;
if (!mark[nxt[i]]) {
++ans;
mark[nxt[i]] = true;
}
else ++ans;
mark[i] = true;
}
cout << ans << '\n';
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
0 ms |
604 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
604 KB |
Output is correct |
2 |
Correct |
0 ms |
604 KB |
Output is correct |
3 |
Correct |
0 ms |
604 KB |
Output is correct |
4 |
Correct |
147 ms |
14088 KB |
Output is correct |
5 |
Correct |
125 ms |
11476 KB |
Output is correct |
6 |
Correct |
133 ms |
14688 KB |
Output is correct |
7 |
Correct |
124 ms |
10788 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
128 ms |
11332 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
0 ms |
604 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |