제출 #510418

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
510418		KoD	Cijanobakterije (COCI21_cijanobakterije)	C++17	70 / 70	67 ms	6908 KiB

Main

#include <bits/stdc++.h>

using std::vector;
using std::array;
using std::pair;
using std::tuple;

int main() {
    std::ios_base::sync_with_stdio(false);
    std::cin.tie(nullptr);
    int N, M;
    std::cin >> N >> M;
    vector<vector<int>> graph(N);
    while (M--) {
        int a, b;
        std::cin >> a >> b;
        a -= 1, b -= 1;
        graph[a].push_back(b);
        graph[b].push_back(a);
    }    
    vector<int> dist(N, -1);
    int ans = 0;
    for (int src = 0; src < N; ++src) {
        if (dist[src] >= 0) continue;
        vector<int> list;
        {
            std::queue<int> que;
            const auto push = [&](const int u, const int d) {
                if (dist[u] == -1) {
                    dist[u] = d;
                    list.push_back(u);
                    que.push(u);
                }
            };
            push(src, 0);
            while (!que.empty()) {
                const int u = que.front();
                que.pop();
                for (const int v : graph[u]) {
                    push(v, dist[u] + 1);
                }
            }
        }
        int s = -1;
        for (const int u : list) {
            if (s == -1 or dist[s] < dist[u]) {
                s = u;
            }
        }
        for (const int u : list) {
            dist[u] = -1;
        }
        {
            std::queue<int> que;
            const auto push = [&](const int u, const int d) {
                if (dist[u] == -1) {
                    dist[u] = d;
                    que.push(u);
                }
            };
            push(s, 0);
            while (!que.empty()) {
                const int u = que.front();
                que.pop();
                for (const int v : graph[u]) {
                    push(v, dist[u] + 1);
                }
            }
        }
        int max = -1;
        for (const int u : list) {
            max = std::max(max, dist[u]);
        }
        ans += max + 1;
    }
    std::cout << ans << '\n';
    return 0;
}

• Subtask 1: 15 / 15
• Subtask 2: 6 / 6
• Subtask 3: 6 / 6
• Subtask 4: 15 / 15
• Subtask 5: 28 / 28