Submission #706513

#	Time	Username	Problem	Language	Result	Execution time	Memory
706513		tamyte	Monthly railway pass (LMIO18_menesinis_bilietas)	C++14	100 / 100	385 ms	30988 KiB

menesinis_bilietas

#include <bits/stdc++.h>


using namespace std;

struct DSU {
    vector<int> e;
    DSU(int n) {
        e = vector<int>(n, -1);
    }
    int get(int x) {
        return e[x] < 0 ? x : e[x] = get(e[x]);
    }
    bool same(int x, int y) {
        return get(x) == get(y);
    }
    int size(int x) {
        return -e[get(x)];
    }
    bool unite(int x, int y) {
//        cout << x << " " << y << " -> ";
        x = get(x), y = get(y);
//        cout << x << " " << y << "\n";
        if (x == y) return false;
        if (e[x] > e[y]) swap(x, y);
        e[x] += e[y];
        e[y] = x;
//        cout << x << " " << y << "\n";
        return true;
    }

};

vector<int> adj[(int)5e5 + 1];


int main() {
    int n, m;
    cin >> n >> m;
    DSU dsu(n);
    if (!m) {
        cout << 0;
        return 0;
    }
    vector<pair<int, int>> bus;
    for (int i = 0; i < m; ++i) {
        int a, b;
        char c;
        cin >> a >> b >> c;
        --a; --b;
        if (c == 'T') {
//            cout << "a";
            dsu.unite(a, b);
        } else {
            bus.push_back({a, b});
        }
    }
//    for (auto u : dsu.e) {
//        cout << u << " ";
//    }
//    cout << "\n";
    bool free = true;
    for (auto u : bus) {
        int x = dsu.get(u.first);
        int y = dsu.get(u.second);
        if (x == y) continue;
        free = false;
        adj[x].push_back(y);
        adj[y].push_back(x);
    }
    // cout << free << "\n";
    if (free) {
        bool connected = true;
        // cerr << "a";
        // cout << "a";
        for (int i = 0; i < n; ++i) {
            if (dsu.get(i) != dsu.get(0)) {
                connected = false;
                break;
            }
        } 
        if (connected) cout << n;
        else cout << 0;
        return 0;
    }
    // cerr << "a";
    int cnt = 0;
    for (int i = 0; i < n; ++i) {
        auto& curr = adj[i];
        if (curr.size()) {
            sort(curr.begin(), curr.end());
            auto it = unique(curr.begin(), curr.end());
            curr.erase(it, curr.end());
            int sum = (dsu.e[i] < 0 ? -dsu.e[i] : 1);
            for (auto& u : curr) {
                sum += -dsu.e[u];
            }
            cnt += (sum == n) * (dsu.e[i] < 0 ? -dsu.e[i] : 1);
        }
    }
    cout << cnt;
}

• Subtask 1: 10 / 10
• Subtask 2: 6 / 6
• Subtask 3: 30 / 30
• Subtask 4: 35 / 35
• Subtask 5: 19 / 19