제출 #1095294

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1095294		Tymond	Love Polygon (BOI18_polygon)	C++17	100 / 100	164 ms	16724 KiB

polygon

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
#define fi first
#define se second
#define vi vector<int>
#define vll vector<long long>
#define pii pair<int, int>
#define pll pair<long long, long long>
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rng64(chrono::steady_clock::now().time_since_epoch().count());
inline int rand(int l,int r){return uniform_int_distribution<int>(l, r)(rng);}
inline ll rand(ll l,ll r){return uniform_int_distribution<ll>(l, r)(rng64);}
#ifdef DEBUG
auto&operator<<(auto&o,pair<auto,auto>p){return o<<"("<<p.first<<", "<<p.second<<")";}
auto operator<<(auto&o,auto x)->decltype(x.end(),o){o<<"{";int i=0;for(auto e:x)o<<","+!i++<<e;return o<<"}";}
#define debug(X...)cerr<<"["#X"]: ",[](auto...$){((cerr<<$<<"; "),...)<<endl;}(X)
#else
#define debug(...){}
#endif
 
struct custom_hash {
    static uint64_t splitmix64(uint64_t x) {
        x += 0x9e3779b97f4a7c15;
        x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
        x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
        return x ^ (x >> 31);
    }
 
    size_t operator()(uint64_t x) const {
        static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
        return splitmix64(x + FIXED_RANDOM);
    }
};

const int MAXN = 1e5 + 7;
int n;
int g[MAXN];
int f[MAXN];
int deg[MAXN];
map<string, int> used;

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(NULL);
    cout.tie(NULL);

    cin >> n;
    int k = 1;
    for(int i = 1; i <= n; i++){
        string s, t;
        cin >> s >> t;
        int aktS = used[s];
        if(aktS == 0){
            used[s] = k++;
            aktS = used[s];
        }

        int aktT = used[t];
        if(aktT == 0){
            used[t] = k++;
            aktT = used[t];
        }

        g[aktS] = aktT;
        deg[aktT]++;
    }

    if(n % 2 == 1){
        cout << -1 << '\n';
        return 0;
    }

    set<pii> s;
    int ans = n;
    for(int i = 1; i <= n; i++){
        if(g[i] != i && g[g[i]] == i){
            ans--;
            f[i] = 1;
            continue;
        }
        s.insert({deg[i], i});
    }

    while(sz(s)){
        pii v = *s.begin();
        s.erase(s.begin());

        if(deg[v.se] != 0){
            break;
        }

        int i = v.se;
        if(g[i] != i && !f[g[i]]){
            f[i] = 1;
            f[g[i]] = 1;
            ans--;
            s.erase({deg[g[i]], g[i]});
            if(!f[g[g[i]]]){
                s.erase({deg[g[g[i]]], g[g[i]]});
                deg[g[g[i]]]--;
                s.insert({deg[g[g[i]]], g[g[i]]});
            }
        }
    }

    vi vec;
    for(int i = 1; i <= n; i++){
        if(!f[i]){
            vec.pb(i);
        }
    }

    for(auto ele : vec){
        if(f[ele]){
            continue;
        }

        int x = 0;
        int ind = ele;
        while(!f[ind]){
            x++;
            f[ind] = 1;
            ind = g[ind];
        }

        ans -= (x / 2);
    }

    cout << ans << '\n';

    return 0;
}

• Subtask 1: 21 / 21
• Subtask 2: 25 / 25
• Subtask 3: 29 / 29
• Subtask 4: 25 / 25