#include <bits/stdc++.h>
using namespace std;
int main(){
int n, ans = 0; cin >> n;
vector<pair<string,string>> in;
vector<int> belove(n), love(n);
map<string,int> M;
queue<int> nobody;
vector<bool> vis(n,false);
if(n & 1){
cout << "-1\n"; return 0;
}
for(int i = 0; i < n; ++i){
string s1, s2; cin >> s1 >> s2;
M[s1] = i;
in.push_back({s1,s2});
}
for(int i = 0; i < n; ++i){
love[M[in[i].first]] = M[in[i].second];
belove[M[in[i].second]]++;
}
for(int i = 0; i < n; ++i){
if(love[love[i]] == i && love[i] != i)vis[i] = true;
if(!belove[i]){nobody.push(i);}
}
while(!nobody.empty()){
auto x = nobody.front();
nobody.pop();
vis[x] = true;
if(!vis[love[x]]){
vis[love[x]] = true;
if(--belove[love[love[x]]] == 0)nobody.push(love[love[x]]);
}
ans++;
}
for(int i = 0; i < n; ++i){
if(!vis[i]){
vis[i] = true;
int last = i;
vis[last] = true;
int cnt = 1;
while(!vis[love[last]]){
cnt++;
last = love[last];
vis[last] = true;
}
ans+=(cnt+1)>>1;
}
}
cout << ans << "\n";
}
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
384 KB |
Output is correct |
| 2 |
Correct |
0 ms |
384 KB |
Output is correct |
| 3 |
Correct |
1 ms |
256 KB |
Output is correct |
| 4 |
Correct |
0 ms |
256 KB |
Output is correct |
| 5 |
Correct |
1 ms |
256 KB |
Output is correct |
| 6 |
Correct |
0 ms |
256 KB |
Output is correct |
| 7 |
Correct |
1 ms |
256 KB |
Output is correct |
| 8 |
Correct |
0 ms |
256 KB |
Output is correct |
| 9 |
Correct |
1 ms |
256 KB |
Output is correct |
| 10 |
Correct |
0 ms |
256 KB |
Output is correct |
| 11 |
Correct |
1 ms |
256 KB |
Output is correct |
| 12 |
Correct |
0 ms |
256 KB |
Output is correct |
| 13 |
Correct |
1 ms |
256 KB |
Output is correct |
| 14 |
Correct |
0 ms |
256 KB |
Output is correct |
| 15 |
Correct |
1 ms |
256 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
256 KB |
Output is correct |
| 2 |
Correct |
1 ms |
256 KB |
Output is correct |
| 3 |
Correct |
0 ms |
256 KB |
Output is correct |
| 4 |
Correct |
376 ms |
17364 KB |
Output is correct |
| 5 |
Correct |
380 ms |
17440 KB |
Output is correct |
| 6 |
Correct |
384 ms |
17544 KB |
Output is correct |
| 7 |
Correct |
1 ms |
1152 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
378 ms |
15448 KB |
Output is correct |
| 2 |
Correct |
381 ms |
15444 KB |
Output is correct |
| 3 |
Correct |
338 ms |
15444 KB |
Output is correct |
| 4 |
Correct |
1 ms |
1152 KB |
Output is correct |
| 5 |
Correct |
391 ms |
15320 KB |
Output is correct |
| 6 |
Correct |
370 ms |
15452 KB |
Output is correct |
| 7 |
Correct |
371 ms |
15480 KB |
Output is correct |
| 8 |
Correct |
358 ms |
15392 KB |
Output is correct |
| 9 |
Correct |
361 ms |
15604 KB |
Output is correct |
| 10 |
Correct |
309 ms |
15724 KB |
Output is correct |
| 11 |
Correct |
0 ms |
256 KB |
Output is correct |
| 12 |
Correct |
0 ms |
256 KB |
Output is correct |
| 13 |
Correct |
1 ms |
256 KB |
Output is correct |
| 14 |
Correct |
0 ms |
256 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
384 KB |
Output is correct |
| 2 |
Correct |
0 ms |
384 KB |
Output is correct |
| 3 |
Correct |
1 ms |
256 KB |
Output is correct |
| 4 |
Correct |
0 ms |
256 KB |
Output is correct |
| 5 |
Correct |
1 ms |
256 KB |
Output is correct |
| 6 |
Correct |
0 ms |
256 KB |
Output is correct |
| 7 |
Correct |
1 ms |
256 KB |
Output is correct |
| 8 |
Correct |
0 ms |
256 KB |
Output is correct |
| 9 |
Correct |
1 ms |
256 KB |
Output is correct |
| 10 |
Correct |
0 ms |
256 KB |
Output is correct |
| 11 |
Correct |
1 ms |
256 KB |
Output is correct |
| 12 |
Correct |
0 ms |
256 KB |
Output is correct |
| 13 |
Correct |
1 ms |
256 KB |
Output is correct |
| 14 |
Correct |
0 ms |
256 KB |
Output is correct |
| 15 |
Correct |
1 ms |
256 KB |
Output is correct |
| 16 |
Correct |
0 ms |
256 KB |
Output is correct |
| 17 |
Correct |
1 ms |
256 KB |
Output is correct |
| 18 |
Correct |
0 ms |
256 KB |
Output is correct |
| 19 |
Correct |
376 ms |
17364 KB |
Output is correct |
| 20 |
Correct |
380 ms |
17440 KB |
Output is correct |
| 21 |
Correct |
384 ms |
17544 KB |
Output is correct |
| 22 |
Correct |
1 ms |
1152 KB |
Output is correct |
| 23 |
Correct |
378 ms |
15448 KB |
Output is correct |
| 24 |
Correct |
381 ms |
15444 KB |
Output is correct |
| 25 |
Correct |
338 ms |
15444 KB |
Output is correct |
| 26 |
Correct |
1 ms |
1152 KB |
Output is correct |
| 27 |
Correct |
391 ms |
15320 KB |
Output is correct |
| 28 |
Correct |
370 ms |
15452 KB |
Output is correct |
| 29 |
Correct |
371 ms |
15480 KB |
Output is correct |
| 30 |
Correct |
358 ms |
15392 KB |
Output is correct |
| 31 |
Correct |
361 ms |
15604 KB |
Output is correct |
| 32 |
Correct |
309 ms |
15724 KB |
Output is correct |
| 33 |
Correct |
0 ms |
256 KB |
Output is correct |
| 34 |
Correct |
0 ms |
256 KB |
Output is correct |
| 35 |
Correct |
1 ms |
256 KB |
Output is correct |
| 36 |
Correct |
0 ms |
256 KB |
Output is correct |
| 37 |
Correct |
375 ms |
17460 KB |
Output is correct |
| 38 |
Correct |
388 ms |
17748 KB |
Output is correct |
| 39 |
Correct |
380 ms |
17748 KB |
Output is correct |
| 40 |
Correct |
383 ms |
17620 KB |
Output is correct |
| 41 |
Correct |
378 ms |
17552 KB |
Output is correct |
| 42 |
Correct |
376 ms |
17492 KB |
Output is correct |
| 43 |
Correct |
374 ms |
17492 KB |
Output is correct |
| 44 |
Correct |
382 ms |
17492 KB |
Output is correct |
| 45 |
Correct |
388 ms |
17620 KB |
Output is correct |
| 46 |
Correct |
377 ms |
17620 KB |
Output is correct |
| 47 |
Correct |
379 ms |
17620 KB |
Output is correct |
| 48 |
Correct |
380 ms |
17552 KB |
Output is correct |
| 49 |
Correct |
383 ms |
17512 KB |
Output is correct |
| 50 |
Correct |
330 ms |
17364 KB |
Output is correct |
| 51 |
Correct |
1 ms |
1152 KB |
Output is correct |
| 52 |
Correct |
416 ms |
17352 KB |
Output is correct |
| 53 |
Correct |
383 ms |
17748 KB |
Output is correct |
| 54 |
Correct |
394 ms |
17588 KB |
Output is correct |
| 55 |
Correct |
352 ms |
17672 KB |
Output is correct |
| 56 |
Correct |
363 ms |
17620 KB |
Output is correct |
| 57 |
Correct |
314 ms |
17880 KB |
Output is correct |
| 58 |
Correct |
1 ms |
256 KB |
Output is correct |
| 59 |
Correct |
0 ms |
256 KB |
Output is correct |
| 60 |
Correct |
0 ms |
256 KB |
Output is correct |
| 61 |
Correct |
1 ms |
256 KB |
Output is correct |
| 62 |
Correct |
0 ms |
256 KB |
Output is correct |
| 63 |
Correct |
1 ms |
256 KB |
Output is correct |
| 64 |
Correct |
1 ms |
256 KB |
Output is correct |
| 65 |
Correct |
385 ms |
17492 KB |
Output is correct |
| 66 |
Correct |
371 ms |
17364 KB |
Output is correct |
| 67 |
Correct |
384 ms |
17620 KB |
Output is correct |
| 68 |
Correct |
1 ms |
1152 KB |
Output is correct |
| 69 |
Correct |
0 ms |
256 KB |
Output is correct |
| 70 |
Correct |
1 ms |
256 KB |
Output is correct |
| 71 |
Correct |
1 ms |
256 KB |
Output is correct |
| 72 |
Correct |
1 ms |
256 KB |
Output is correct |
| 73 |
Correct |
1 ms |
256 KB |
Output is correct |
| 74 |
Correct |
1 ms |
256 KB |
Output is correct |
| 75 |
Correct |
1 ms |
256 KB |
Output is correct |
| 76 |
Correct |
1 ms |
256 KB |
Output is correct |
| 77 |
Correct |
0 ms |
256 KB |
Output is correct |
| 78 |
Correct |
0 ms |
256 KB |
Output is correct |
| 79 |
Correct |
1 ms |
256 KB |
Output is correct |
| 80 |
Correct |
1 ms |
256 KB |
Output is correct |
| 81 |
Correct |
1 ms |
384 KB |
Output is correct |
| 82 |
Correct |
0 ms |
256 KB |
Output is correct |
| 83 |
Correct |
1 ms |
256 KB |
Output is correct |
