#include <bits/stdc++.h>
#include <math.h>
//in the name of god,aka allah
//**gray sety orz**
using namespace std;
#define pi pair<long long , long long>
#define pii pair<long long , pair<long long , long long>>
const int maxm = 5e5;
const long long mod = 1e9 + 7 ;
typedef long long ll;
ll l,r,mid;
ll n,m;
ll darage[maxm] , ss , mm;
queue<int> q;
bool vis[maxm];
ll pedaret[maxm];
set<string> st;
ll rp[maxm];
map<string,ll> mp;
inline void bfs(){
mid = 0;
while(!q.empty()){
int u = q.front(); q.pop();
mid++; vis[u] = 1;
if(!vis[pedaret[u]]){
if(--darage[pedaret[pedaret[u]]] == 0 && !vis[pedaret[pedaret[u]]]) q.push(pedaret[pedaret[u]]);
vis[pedaret[u]] = 1;
}
}
}
int pe(string s){
if(st.find(s)==st.end()) mp.insert({s,mp.size()}) , st.insert(s);
return mp[s];
}
int main() {
ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
cin>>n;
if(n%2) return cout<<-1,0;
for(int i = 0; i<n; i++){
string s,t;
cin>>s>>t;
l=pe(s);
r=pe(t);
pedaret[l]=r;
darage[r]++;
}
for(int i=0; i<n; i++) if(pedaret[pedaret[i]]==i && pedaret[i]!=i) vis[i] = 1,vis[pedaret[i]] = 1;
for(int i = 0; i<n; i++) if(darage[i]==0&&vis[i]==0) q.push(i);
for(int i=0; i<n; i++){
if(!vis[i]){
r=1;
vis[i]=1;
int j = pedaret[i];
while(j!=i){ vis[j] = 1, j = pedaret[j]} r++;
mid+=(r+1)/2;
}
}
cout<<mid;
}
Compilation message
polygon.cpp: In function 'int main()':
polygon.cpp:54:52: error: expected ';' before '}' token
54 | while(j!=i){ vis[j] = 1, j = pedaret[j]} r++;
| ^
| ;
