Submission #1059531

#	Time	Username	Problem	Language	Result	Execution time	Memory
1059531		Thanhs	Cijanobakterije (COCI21_cijanobakterije)	C++14	70 / 70	35 ms	19660 KiB

Main

#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
using namespace std;
#define int long long
// #define double long double
 
#define endl '\n'
#define fastIO ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);
#define setmin(x, y) x = min((x), (y))
#define setmax(x, y) x = max((x), (y))
#define sqr(x) ((x) * (x))
#define fi first
#define se second
#define all(x) x.begin(), x.end()
 
// mt19937 hdp(chrono::high_resolution_clock::now().time_since_epoch().count());
// int rand(int l, int r){return l + ((hdp() % (r - l + 1)) + r - l + 1) % (r - l + 1);}

const int NM = 1e5 + 5;
const int LM = 1e4 + 5;
const int mod = 1e9 + 7;

vector<int> g[NM];
vector<pair<int, int>> V;
int ans, n, m, dep[NM], d, vis[NM];

void dfs(int u, int p = 0)
{
    vis[u] = 1;
    V.push_back({dep[u], u});
    for (int v : g[u])
        if (v != p)
        {
            dep[v] = dep[u] + 1;
            dfs(v, u);
        }
}

void DFS(int u, int l, int p = 0)
{
    setmax(d, l);
    for (int v : g[u])
        if (v != p)
            DFS(v, l + 1, u);
}

void solve()
{
    cin >> n >> m;
    while (m--)
    {
        int u, v;
        cin >> u >> v;
        g[u].push_back(v);
        g[v].push_back(u);
    }
    for (int i = 1; i <= n; i++)
        if (!vis[i])
        {
            V.clear();
            dfs(i);
            int u = (*max_element(V.begin(), V.end())).se;
            d = 1;
            DFS(u, 1);
            ans += d;
        }
    cout << ans << endl;
}

signed main()
{
    fastIO
    if (fopen("in.txt", "r")) 
    {
        freopen("in.txt", "r", stdin);
        freopen("out.txt", "w", stdout);
    }
    int tc = 1;
    // cin >> tc;
    while (tc--)
        solve();
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:76:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   76 |         freopen("in.txt", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
Main.cpp:77:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   77 |         freopen("out.txt", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

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