Submission #745450

#	Time	Username	Problem	Language	Result	Execution time	Memory
745450		Alexandruabcde	Marshmallow Molecules (CCO19_day2problem2)	C++14	25 / 25	140 ms	24576 KiB

Main

#include <bits/stdc++.h>

using namespace std;

typedef pair <int, int> PII;
constexpr int NMAX = 1e5 + 5;

int N, M;
set <int> G[NMAX];

map <PII, int> mp;

void Unite (int x, int y) {
    if (G[x].size() > G[y].size()) swap(G[x], G[y]);

    for (auto it : G[x])
        G[y].insert(it);
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    cin >> N >> M;

    for (int i = 1; i <= M; ++ i ) {
        int x, y;
        cin >> x >> y;

        if (x > y) swap(x, y);
        G[x].insert(y);
    }

    long long answer = 0;
    for (int i = 1; i <= N; ++ i ) {
        answer += 1LL * G[i].size();

        if (G[i].empty()) continue;

        auto it = G[i].begin();
        G[i].erase(it);

        Unite(i, *it);
    }

    cout << answer << '\n';

    return 0;
}

• Subtask 1: 5 / 5
• Subtask 2: 5 / 5
• Subtask 3: 5 / 5
• Subtask 4: 10 / 10