#pragma GCC optimize("Ofast,O2,O3,unroll-loops")
#pragma GCC target("avx2")
#include <bits/stdc++.h>
#include <random>
using namespace std;
void debug_out() { cerr << endl; }
template<typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
cerr << "[" << H << "]";
debug_out(T...);
}
#ifdef dddxxz
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif
#define SZ(s) ((int)s.size())
#define all(x) (x).begin(), (x).end()
#define lla(x) (x).rbegin(), (x).rend()
#define bpc(x) __builtin_popcount(x)
#define bpcll(x) __builtin_popcountll(x)
clock_t startTime;
double getCurrentTime() {
return (double) (clock() - startTime) / CLOCKS_PER_SEC;
}
#define MP make_pair
typedef long long ll;
mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
const double eps = 0.000001;
const int MOD = 1e9 + 7;
const int INF = 1000000101;
const long long LLINF = 1223372000000000555;
const int N = 1e6 + 3e2;
const int M = 1111;
map<string, int> mp;
int id(const string &s){
if (mp.find(s) != mp.end()) return mp[s];
return mp[s] = mp.size() + 1;
}
int f[N];
bool used[N];
int cnt[N];
set<int> s[N];
void solve(int TC) {
int n;
cin >> n;
if (n & 1){
cout << -1;
return;
}
for (int i = 1; i <= n; i++){
string x, y;
cin >> x >> y;
f[id(x)] = id(y);
// cout << id(x) << ' ' << id(y) << endl;
}
// cout << endl;
for (int i = 1; i <= n; i++){
if (!used[i] && !used[f[i]] && f[f[i]] == i && f[i] != i){
used[i] = true;
used[f[i]] = true;
}
}
for (int i = 1; i <= n; i++){
if (f[i] != i && !used[i] && !used[f[i]]) s[f[i]].insert(i);
}
set<pair<int, int>> S;
for (int i = 1; i <= n; i++){
if (f[i] != i && !used[i] && !used[f[i]]) S.insert(MP(s[i].size(), i));
}
int ans = 0;
while (!S.empty()){
int i = S.begin()->second;
S.erase(MP(s[i].size(), i));
S.erase(MP(s[f[i]].size(), f[i]));
ans++;
used[i] = true;
used[f[i]] = true;
for (int j : s[i]) S.erase(MP(s[j].size(), j));
for (int j : s[f[i]]) S.erase(MP(s[j].size(), j));
int j = f[f[i]];
if (S.count(MP(s[j].size(), j))){
S.erase(MP(s[j].size(), j));
s[j].erase(f[i]);
if (!used[j] && !used[f[j]] && f[j] != j) S.insert(MP(s[j].size(), j));
}
}
for (int i = 1; i <= n; i++) ans += !used[i];
// for (int i = 1; i <= n; i++) cout << used[i] << ' '; cout << endl;
cout << ans << endl;
}
int main() {
startTime = clock();
ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);
#ifdef dddxxz
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif
int TC = 1;
// cin >> TC;
for (int test = 1; test <= TC; test++) {
//debug(test);
//cout << "Case #" << test << ": ";
solve(test);
}
#ifdef dddxxz
cerr << endl << "Time: " << int(getCurrentTime() * 1000) << " ms" << endl;
#endif
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
24 ms |
47316 KB |
Output is correct |
2 |
Correct |
28 ms |
47296 KB |
Output is correct |
3 |
Correct |
26 ms |
47316 KB |
Output is correct |
4 |
Correct |
33 ms |
47300 KB |
Output is correct |
5 |
Correct |
30 ms |
47316 KB |
Output is correct |
6 |
Correct |
27 ms |
47208 KB |
Output is correct |
7 |
Correct |
27 ms |
47320 KB |
Output is correct |
8 |
Correct |
29 ms |
47236 KB |
Output is correct |
9 |
Correct |
28 ms |
47320 KB |
Output is correct |
10 |
Correct |
26 ms |
47216 KB |
Output is correct |
11 |
Correct |
31 ms |
47304 KB |
Output is correct |
12 |
Correct |
31 ms |
47308 KB |
Output is correct |
13 |
Correct |
27 ms |
47272 KB |
Output is correct |
14 |
Correct |
26 ms |
47316 KB |
Output is correct |
15 |
Correct |
26 ms |
47288 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
29 ms |
47320 KB |
Output is correct |
2 |
Correct |
28 ms |
47316 KB |
Output is correct |
3 |
Correct |
27 ms |
47252 KB |
Output is correct |
4 |
Correct |
293 ms |
65100 KB |
Output is correct |
5 |
Correct |
270 ms |
64596 KB |
Output is correct |
6 |
Correct |
282 ms |
65280 KB |
Output is correct |
7 |
Correct |
26 ms |
47180 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
275 ms |
65040 KB |
Output is correct |
2 |
Correct |
272 ms |
67192 KB |
Output is correct |
3 |
Correct |
151 ms |
57616 KB |
Output is correct |
4 |
Correct |
26 ms |
47324 KB |
Output is correct |
5 |
Correct |
268 ms |
67092 KB |
Output is correct |
6 |
Correct |
264 ms |
67116 KB |
Output is correct |
7 |
Correct |
247 ms |
67140 KB |
Output is correct |
8 |
Correct |
188 ms |
62472 KB |
Output is correct |
9 |
Correct |
238 ms |
67172 KB |
Output is correct |
10 |
Correct |
183 ms |
66972 KB |
Output is correct |
11 |
Correct |
31 ms |
47308 KB |
Output is correct |
12 |
Correct |
26 ms |
47292 KB |
Output is correct |
13 |
Correct |
26 ms |
47280 KB |
Output is correct |
14 |
Correct |
25 ms |
47240 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
24 ms |
47316 KB |
Output is correct |
2 |
Correct |
28 ms |
47296 KB |
Output is correct |
3 |
Correct |
26 ms |
47316 KB |
Output is correct |
4 |
Correct |
33 ms |
47300 KB |
Output is correct |
5 |
Correct |
30 ms |
47316 KB |
Output is correct |
6 |
Correct |
27 ms |
47208 KB |
Output is correct |
7 |
Correct |
27 ms |
47320 KB |
Output is correct |
8 |
Correct |
29 ms |
47236 KB |
Output is correct |
9 |
Correct |
28 ms |
47320 KB |
Output is correct |
10 |
Correct |
26 ms |
47216 KB |
Output is correct |
11 |
Correct |
31 ms |
47304 KB |
Output is correct |
12 |
Correct |
31 ms |
47308 KB |
Output is correct |
13 |
Correct |
27 ms |
47272 KB |
Output is correct |
14 |
Correct |
26 ms |
47316 KB |
Output is correct |
15 |
Correct |
26 ms |
47288 KB |
Output is correct |
16 |
Correct |
29 ms |
47320 KB |
Output is correct |
17 |
Correct |
28 ms |
47316 KB |
Output is correct |
18 |
Correct |
27 ms |
47252 KB |
Output is correct |
19 |
Correct |
293 ms |
65100 KB |
Output is correct |
20 |
Correct |
270 ms |
64596 KB |
Output is correct |
21 |
Correct |
282 ms |
65280 KB |
Output is correct |
22 |
Correct |
26 ms |
47180 KB |
Output is correct |
23 |
Correct |
275 ms |
65040 KB |
Output is correct |
24 |
Correct |
272 ms |
67192 KB |
Output is correct |
25 |
Correct |
151 ms |
57616 KB |
Output is correct |
26 |
Correct |
26 ms |
47324 KB |
Output is correct |
27 |
Correct |
268 ms |
67092 KB |
Output is correct |
28 |
Correct |
264 ms |
67116 KB |
Output is correct |
29 |
Correct |
247 ms |
67140 KB |
Output is correct |
30 |
Correct |
188 ms |
62472 KB |
Output is correct |
31 |
Correct |
238 ms |
67172 KB |
Output is correct |
32 |
Correct |
183 ms |
66972 KB |
Output is correct |
33 |
Correct |
31 ms |
47308 KB |
Output is correct |
34 |
Correct |
26 ms |
47292 KB |
Output is correct |
35 |
Correct |
26 ms |
47280 KB |
Output is correct |
36 |
Correct |
25 ms |
47240 KB |
Output is correct |
37 |
Correct |
258 ms |
67236 KB |
Output is correct |
38 |
Correct |
252 ms |
67180 KB |
Output is correct |
39 |
Correct |
269 ms |
66728 KB |
Output is correct |
40 |
Correct |
288 ms |
67084 KB |
Output is correct |
41 |
Correct |
248 ms |
67148 KB |
Output is correct |
42 |
Correct |
299 ms |
67220 KB |
Output is correct |
43 |
Correct |
295 ms |
67076 KB |
Output is correct |
44 |
Correct |
291 ms |
67072 KB |
Output is correct |
45 |
Correct |
286 ms |
67064 KB |
Output is correct |
46 |
Correct |
311 ms |
67056 KB |
Output is correct |
47 |
Correct |
262 ms |
67172 KB |
Output is correct |
48 |
Correct |
273 ms |
67020 KB |
Output is correct |
49 |
Correct |
260 ms |
67120 KB |
Output is correct |
50 |
Correct |
184 ms |
57588 KB |
Output is correct |
51 |
Correct |
27 ms |
47300 KB |
Output is correct |
52 |
Correct |
287 ms |
67060 KB |
Output is correct |
53 |
Correct |
259 ms |
67176 KB |
Output is correct |
54 |
Correct |
254 ms |
67052 KB |
Output is correct |
55 |
Correct |
215 ms |
62484 KB |
Output is correct |
56 |
Correct |
258 ms |
67088 KB |
Output is correct |
57 |
Correct |
199 ms |
67020 KB |
Output is correct |
58 |
Correct |
26 ms |
47316 KB |
Output is correct |
59 |
Correct |
27 ms |
47316 KB |
Output is correct |
60 |
Correct |
29 ms |
47216 KB |
Output is correct |
61 |
Correct |
26 ms |
47228 KB |
Output is correct |
62 |
Correct |
27 ms |
47300 KB |
Output is correct |
63 |
Correct |
28 ms |
47308 KB |
Output is correct |
64 |
Correct |
27 ms |
47316 KB |
Output is correct |
65 |
Correct |
276 ms |
67148 KB |
Output is correct |
66 |
Correct |
244 ms |
66540 KB |
Output is correct |
67 |
Correct |
276 ms |
67060 KB |
Output is correct |
68 |
Correct |
26 ms |
47300 KB |
Output is correct |
69 |
Correct |
26 ms |
47316 KB |
Output is correct |
70 |
Correct |
30 ms |
47308 KB |
Output is correct |
71 |
Correct |
25 ms |
47228 KB |
Output is correct |
72 |
Correct |
27 ms |
47324 KB |
Output is correct |
73 |
Correct |
27 ms |
47296 KB |
Output is correct |
74 |
Correct |
25 ms |
47316 KB |
Output is correct |
75 |
Correct |
29 ms |
47304 KB |
Output is correct |
76 |
Correct |
26 ms |
47292 KB |
Output is correct |
77 |
Correct |
26 ms |
47316 KB |
Output is correct |
78 |
Correct |
25 ms |
47312 KB |
Output is correct |
79 |
Correct |
26 ms |
47316 KB |
Output is correct |
80 |
Correct |
25 ms |
47316 KB |
Output is correct |
81 |
Correct |
29 ms |
47316 KB |
Output is correct |
82 |
Correct |
27 ms |
47304 KB |
Output is correct |
83 |
Correct |
27 ms |
47248 KB |
Output is correct |