#pragma GCC optimize("O1,O2,O3,Ofast,unroll-loops")
#include <bits/stdc++.h>
#include <string>
#include <iostream>
#include <cmath>
#include <numeric>
#include <stack>
#include <queue>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int, int> pi;
typedef pair<ll, ll> pl;
typedef pair<ld, ld> pd;
typedef vector<int> vi;
typedef vector<bool> vb;
typedef vector<vector<int>> vvi;
typedef vector<vector<pi>> vvpi;
typedef vector<ld> vd;
typedef vector<long long> vl;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
#define FOR(i, a, b) for (int i = a; i < (b); i++)
#define F0R(i, a) for (int i = 0; i < (a); i++)
#define FORd(i, a, b) for (int i = (b)-1; i >= a; i--)
#define F0Rd(i, a) for (int i = (a)-1; i >= 0; i--)
#define trav(a, x) for (auto &a : x)
#define uid(a, b) uniform_int_distribution<int>(a, b)(rng)
#define len(x) (int)(x).size()
#define mp make_pair
#define pb push_back
#define F first
#define nl endl
#define S second
#define lb lower_bound
#define ub upper_bound
#define aint(x) x.begin(), x.end()
#define raint(x) x.rbegin(), x.rend()
#define ins insert
const int M = 1e9+7;
void init(string name)
{
freopen((name + ".in").c_str(), "r", stdin);
freopen((name + ".out").c_str(), "w", stdout);
}
void fastIO()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
}
int n;
map <string,int> arr;
vvi paths(1e5+10,vi());
int cnt = 0;
vi visited(1e5+10,0);
int len = 0;
int add_to(string a){
if(arr.count(a)>0){
return arr[a];
}else{
arr[a] = cnt;
cnt ++;
return cnt-1;
}
}
void dfs(int pos){
if(visited[pos])return;
visited[pos] = 1;
len ++;
if(paths[pos].size() > 1)dfs(paths[pos][0]);
// for(int a:paths[pos])dfs(a);
}
void solve()
{
cin >> n;
FOR(i,0,n){
string a,b;
cin >> a >> b;
int c = add_to(a),d= add_to(b);
paths[c].pb(d);
cerr << c << " -> " << d << endl;
}
if(cnt%2 == 1){
cout << -1 << endl;
return;
}
int ones = 0,ans = 0;
FOR(i,0,cnt){
len = 0;
dfs(i);
cerr << i << " " << len << endl;
ones += (len%2);
ans += len/2;
}
cerr << "ones " << ones << endl;
ans += ones;
cout << ans << endl;
}
int main()
{
fastIO();
// init("test");
int t = 1;
// cin >> t;
while (t--)
solve();
return 0;
}
Compilation message
polygon.cpp: In function 'void init(std::string)':
polygon.cpp:44:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
44 | freopen((name + ".in").c_str(), "r", stdin);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
polygon.cpp:45:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
45 | freopen((name + ".out").c_str(), "w", stdout);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
2 ms |
3164 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
3164 KB |
Output is correct |
| 2 |
Incorrect |
1 ms |
3164 KB |
Output isn't correct |
| 3 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
794 ms |
16232 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
2 ms |
3164 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
