Submission #1216939

#	Time	Username	Problem	Language	Result	Execution time	Memory
1216939		friendiks	Love Polygon (BOI18_polygon)	C++20	29 / 100	188 ms	16836 KiB

polygon

#ifndef LOCAL
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#pragma GCC diagnostic ignored "-Wpedantic"
#endif

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

auto seed = chrono::high_resolution_clock::now().time_since_epoch().count();
mt19937 rnd(52);
template<typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<typename T, typename V>
using table = gp_hash_table<T, V>;

using i128 = __int128;
using ll = long long;
using ld = long double;
using uint = unsigned int;
using ull = unsigned long long;

const ll INF = 2e18;
const int inf = 1e9;
const int maxn = 1e5 + 7;
const int MOD = 1e9 + 7;
const ld pi = acos(-1);
const int P = 5167;
const int L = 26;
const ld EPS = 1e-7;

template<typename T, typename V>
void fill(T &container, V value) {
    for (auto &c : container)
        c = value;
}

vector<int> g[maxn];
int dp[maxn];

void dfs(int v) {
    for (auto to : g[v]) {
        dfs(to);
        dp[v] = max(dp[v], 1 - dp[to]);
    }
}

void solve() {
    int n;
    cin >> n;
    if (n % 2 == 1) {
        cout << -1;
        return;
    }
    map<string, int> mp;
    int curr = 1;
    vector<int> roots;
    for (int i = 0; i < n; ++i) {
        string s, t;
        cin >> s >> t;
        if (mp[s] == 0) mp[s] = curr++;
        if (mp[t] == 0) mp[t] = curr++;
        if (s == t) roots.push_back(mp[s]);
        else g[mp[t]].push_back(mp[s]);
    }
    for (auto root : roots) {
        dfs(root);
    }
    int ans = n;
    for (auto c : dp) {
        ans -= c;
    }
    cout << ans;
}

signed main() {
#ifdef LOCAL
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout << fixed << setprecision(4);
    int t = 1;
    //cin >> t;
    while (t--) solve();
    //stress();
}

• Subtask 1: 0 / 21
• Subtask 2: 0 / 25
• Subtask 3: 29 / 29
• Subtask 4: 0 / 25