/* Author : Mychecksdead */
#include<bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef long double ld;
#define MOD (1000000000+7)
#define MOD1 (998244353)
#define PI 3.1415926535
#define pb push_back
#define setp() cout << setprecision(15)
#define all(x) x.begin(), x.end()
#define debug(x) cerr << #x << " is " << x << '\n';
const int N = 1e6+100, M = 1e5+10, F = 2147483646, K = 20;
int n, to[N], res = 0, dp[N][2];
string x, y;
vector<int> in(N), g[N];
map<string, int> s;
vector<bool> vis(N), is(N);
void dfs(int v, int d){
vis[v] = 1;
int u = to[v];
if(vis[u]){
if(d > 2) res += (d+1)/2;
else if(d == 1) res++;
}else dfs(u, d + 1);
}
void dfs1(int v){
dp[v][0] = dp[v][1] = MOD;
if(g[v].size() == 0){
dp[v][0] = dp[v][1] = 1;
}
dp[v][0] = 1;
int sum = 0;
for(int u: g[v]){
dfs1(u);
dp[v][0] += min(dp[u][0], dp[u][1]);
sum += dp[u][1];
}
for(int u: g[v]){
dp[v][1] = min(dp[v][1], sum - dp[u][1] + dp[u][0] - 1);
}
}
void solve(){
cin >> n;
int c = 1;
for(int i = 0; i < n; ++i){
cin >> x >> y;
if(s[x] == 0) s[x] = c++;
if(s[y] == 0) s[y] = c++;
int a = s[x] - 1, b = s[y] - 1;
to[a] = b;
is[b] = 1;
g[b].pb(a);
}
if(n&1){
cout << -1;
return;
}
if(n <= 20){
int ans = n;
for(int mask = 0; mask < (1<<n); ++mask){
bool ok = 1;
vector<int> v;
for(int j = 0; j < n; ++j){
if(!((1<<j)&mask)){
v.pb(to[j]);
if(to[j] == j) ok = 0;
else if(!(to[to[j]] == j || ((1<<to[j])&mask))) ok = 0;
}
}
sort(all(v));
for(int j = 0; j < int(v.size()) - 1; ++j) if(v[j] == v[j + 1]) ok = 0;
if(ok){
if(ans > __builtin_popcount(mask)){
ans = __builtin_popcount(mask);
}
}
}
cout << ans;
return;
}
bool ok = 1;
for(int i = 0; i < n; ++i) ok &= is[i];
if(ok)
for(int i = 0; i < n; ++i) if(!vis[i]) dfs(i, 1);
else
for(int i = 0; i < n; ++i) if(to[i] == i) dfs1(i), res += min(dp[i][0], dp[i][1]);
cout << res;
}
int main(){
cin.tie(0); ios::sync_with_stdio(0);
int T = 1, aa;
// cin >> T;aa=T;
while(T--){
// cout << "Case #" << aa-T << ": ";
solve();
cout << '\n';
}
return 0;
}
Compilation message
polygon.cpp: In function 'void solve()':
polygon.cpp:92:7: warning: suggest explicit braces to avoid ambiguous 'else' [-Wdangling-else]
92 | if(ok)
| ^
polygon.cpp: In function 'int main()':
polygon.cpp:105:16: warning: unused variable 'aa' [-Wunused-variable]
105 | int T = 1, aa;
| ^~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
276 ms |
27988 KB |
Output is correct |
2 |
Correct |
250 ms |
27972 KB |
Output is correct |
3 |
Correct |
298 ms |
27988 KB |
Output is correct |
4 |
Correct |
17 ms |
27920 KB |
Output is correct |
5 |
Correct |
13 ms |
27988 KB |
Output is correct |
6 |
Correct |
13 ms |
27988 KB |
Output is correct |
7 |
Correct |
290 ms |
27972 KB |
Output is correct |
8 |
Correct |
309 ms |
27988 KB |
Output is correct |
9 |
Correct |
273 ms |
28116 KB |
Output is correct |
10 |
Correct |
297 ms |
27988 KB |
Output is correct |
11 |
Correct |
289 ms |
27988 KB |
Output is correct |
12 |
Correct |
17 ms |
28012 KB |
Output is correct |
13 |
Correct |
15 ms |
27988 KB |
Output is correct |
14 |
Correct |
14 ms |
27988 KB |
Output is correct |
15 |
Correct |
13 ms |
27984 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
13 ms |
27988 KB |
Output is correct |
2 |
Correct |
13 ms |
27956 KB |
Output is correct |
3 |
Correct |
15 ms |
28076 KB |
Output is correct |
4 |
Runtime error |
602 ms |
1048576 KB |
Execution killed with signal 9 |
5 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
226 ms |
40412 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
276 ms |
27988 KB |
Output is correct |
2 |
Correct |
250 ms |
27972 KB |
Output is correct |
3 |
Correct |
298 ms |
27988 KB |
Output is correct |
4 |
Correct |
17 ms |
27920 KB |
Output is correct |
5 |
Correct |
13 ms |
27988 KB |
Output is correct |
6 |
Correct |
13 ms |
27988 KB |
Output is correct |
7 |
Correct |
290 ms |
27972 KB |
Output is correct |
8 |
Correct |
309 ms |
27988 KB |
Output is correct |
9 |
Correct |
273 ms |
28116 KB |
Output is correct |
10 |
Correct |
297 ms |
27988 KB |
Output is correct |
11 |
Correct |
289 ms |
27988 KB |
Output is correct |
12 |
Correct |
17 ms |
28012 KB |
Output is correct |
13 |
Correct |
15 ms |
27988 KB |
Output is correct |
14 |
Correct |
14 ms |
27988 KB |
Output is correct |
15 |
Correct |
13 ms |
27984 KB |
Output is correct |
16 |
Correct |
13 ms |
27988 KB |
Output is correct |
17 |
Correct |
13 ms |
27956 KB |
Output is correct |
18 |
Correct |
15 ms |
28076 KB |
Output is correct |
19 |
Runtime error |
602 ms |
1048576 KB |
Execution killed with signal 9 |
20 |
Halted |
0 ms |
0 KB |
- |